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Oster French Door vs Mueller 4 Slice Toaster Oven Side-by-Side Comparison

Alan Nguyen
Reviewer
Nguyen Ntk
Visual Specialist
Updated
Tested Using Methodology v1.0
Updated Apr 3, 2023
Tested Using Methodology v1.0
Updated Apr 3, 2023
The front of a closed Oster TSSTTVFDDG XL Digital French Door Convection Toaster Oven. The control panel is positioned vertically on the right. Inside the oven are a shining light, two baking racks, and one baking pan.
The front of a closed stainless steel Mueller MT-175 4-Slice Countertop Toaster Oven on a white background.

Our Verdict

6.5
Overall Score
  • Performance (50%)
    6.4/10
  • Design (25%)
    6.7/10
  • Usability (25%)
    6.4/10
6.1
Overall Score
  • Performance (50%)
    7.0/10
  • Design (25%)
    5.3/10
  • Usability (25%)
    5.2/10

The Oster French Door Digital Convection Toaster Oven (TSSTTVFDDG) and the Mueller 4 Slice (MT-175) are polar opposites in terms of design. Their overall scores, however, don’t differ as much and do bring up some interesting strengths and weaknesses of each individual.

Looking at the design usability ratings, things aren’t too optimistic for the Mueller. As a small unit, the Mueller lacks the convection system and interior light that the extra large Oster has. The Mueller has precise analog control dials but no digital display showing the exact timer and temperature like the Oster.

The Mueller has a detachable crumb tray that makes cleaning the interior easier. Meanwhile, the Oster has a removable crumb tray and a single-pull french door that looks aesthetically pleasing.

In a surprising turn of event, what closed the gap between the two toaster oven was the Mueller’s higher performance score. Despite its lower power output, the Mueller’s was better at baking pizza and especially toasting bread—our most crucial cooking test.

The Oster was better at roasting whole chicken thanks to its convection system. However, we thought the Oster’s cooking chamber was too large in ratio to its power output and the oven didn’t do much better than the Mueller at baking fries.

Medium Heat Only

Oster French Door Toaster Oven Performance

Mueller 4-Slice Toaster Oven Performance: Good Heat Distribution
6.4
Performance Scores
  • Toast (40%)6.0/10
  • Pizza (25%)6.3/10
  • Whole Roasted Chicken (25%)8.1/10
  • Baked French Fries (10%)4.1/10
7.0
Performance Scores
  • Toast (40%)7.5/10
  • Pizza (25%)7.6/10
  • Whole Roasted Chicken (25%)7.0/10
  • Baked French Fries (10%)3.6/10
6.0

Toast

7.5
Oster French Door Toaster Oven Toast Test
From left to right, 24 pieces of toast for three toast levels including lighter, medium, and darker. On the upper row are the top sides, and on the lower row are the bottom sides of the toast.
The best four pieces of toast from the Oster TSSTTVFDDG XL Digital French Door Convection Toaster Oven. On the left are the top sides, and on the right are the bottom sides of the toast.
On the left are four pieces of toast from the first batch, and on the right are from the second batch. On the upper row are the top sides, and on the lower row are the bottom sides.
Taste: 6
50% * 6 = 3.0
Even Surface Color: 6
20% * 6 = 1.2
Consecutive Usability: 6
30% * 6 = 1.8
  • Function: Toast
  • Number Of Slices: 4
  • Toast Level: 4/6
  • Cooking Time: 7m 25s
  • Second Batch: 5m 31s
  • Convection: No

We began our Toast test on the Oster with the default toast level 4 and got pretty good results right off the bat. For good measure, we continued to try the toast level 3, which failed to color evenly within the stipulated time.

We then tried level 5 only to end up with burnt toast and not the expected deep brown shade. Regretfully, while level 4 was the best toast level, it didn’t score high on our benchmark scale—only 6/10.

On this setting—7 minutes 25 seconds on the timer—the four pieces of bread on the upper tray were toasted to a nice golden brown color. However, the color became dark towards the edges, especially where the bread was less dense.

Additionally, a large portion of the bottom right piece of toast was significantly lighter, possibly indicating a cold spot in the cooking chamber. With such unevenness, we could only score the surface color a 6/10 despite the overall golden brown hue.

Moreover, due to the lengthy toasting time, the toast became very crispy but dry on the inside. Our head chef, Tuyet Pham, said this crispiness would be great for eggs benedict and especially soup, but maybe not omelets and sandwiches. Unfortunately, the dark edges produced a bitter taste, preventing it from getting higher than a 6/10 from our chef.

We toasted the second batch of four slices immediately after the first. We chose level 4 again whereupon the oven automatically calibrated the timer to 5 minutes 31 seconds.

Since the oven was already hot, the aforementioned cold spot became less apparent. The toast was not as crispy nor dry as the first batch, which made it more suitable for sandwiches and omelets.

However, the burnt edges were still a problem, so the oven received one final 6/10 for consecutive usability. If you want better results for the second batch, we recommend decreasing the toast level by one.

Mueller 4 Slice Toaster Oven Toast Test
From left to right, 24 pieces of toast for the top and bottom of three toast levels including lighter, medium, and darker.
The top and bottom of the best four pieces of toast from the stainless steel Mueller MT-175 4-Slice Countertop Toaster Oven.
On the left are the top and bottom of four pieces of toast from the first batch, and on the right are from the second batch.
Taste: 8
50% * 8 = 4.0
Even Surface Color: 7
20% * 7 = 1.4
Consecutive Usability: 7
30% * 7 = 2.1
  • Function: Toast
  • Number Of Slices: 4
  • Toast Level: ⅓ to Dark
  • Cooking Time: 4m
  • Second Batch: 4m
  • Convection: No

For our Toast test, we started off by trying the Medium Toast setting which was around 3 minutes 5 seconds on the timer. The four pieces of bread on the upper tray level came out only lightly toasted on top except for one golden brown piece. We then cranked it up to the Dark Toast setting—around 4 minutes 50 seconds on the timer—which, unfortunately, burnt the toast a bit.

Finally, we opted for the middle ground which was 4 minutes on the timer—⅓ of the rotation from Medium to Dark. This setting was tricky to get right on the time dial, so we used an external timer. It gave us the best possible toast results from this oven scoring a 7.5/10 in total.

After 4 minutes of toasting, the four pieces of toast had pretty good surface color. However, the colors varied from light golden to golden brown on both the top and the bottom, so we could only give a 7/10.

Luckily, the varied colors partially meant varied textures which were all good and deserving an 8/10. The golden brown areas had a more crispy outside while the light golden areas had a softer inside. Our head chef Tuyet Pham determined that it would go great with omelets, eggs benedict, and sandwiches but not so much with soup.

After taking out the first batch, we immediately put four more pieces inside to test the oven’s consecutive usability which ended up at 7/10. Also under the identical toasting time, the four pieces of bread became brown with an increased evenness from the first batch. While the color was a bit darker than ideal, the extra crispiness made the second batch more suitable for soups.

6.3

Pizza

7.6
Oster French Door Toaster Oven Pizza Test
A toaster oven baked 9-inch thick-crust meat pizza with cheese, onions, and green bell peppers on top. The pizza is inside a grooved silver baking pan on a white background.
Two slices of toaster oven baked pizza on top of one another. It’s a 9-inch thick-crust meat pizza with cheese, onions, and green bell peppers on top. The pizza is inside a grooved silver baking pan.
On a white background, two hands break apart a slice of baked pizza using a toaster oven with cheese, meat, and green bell peppers on top.
Cooking Time: 9
20% * 9 = 1.8
Crust: 5.5
20% * 5.5 = 1.1
Toppings: 6
30% * 6 = 1.8
Taste: 5.5
30% * 5.5 = 1.6
  • Function: Turbo Convection
  • Temperature: 450°F
  • Cooking Time: 6m
  • Convection: Yes

For this pizza test, we didn’t choose the oven’s 400°F pizza preset because it didn’t match our Pizza test requirement of 450°F. Instead, we chose Turbo Convection as a suitable setting for baking pizza. Nonetheless, the results were not so favorable scoring only 6.4/10 on our testing scale.

We were, however, impressed that the oven only took 9 minutes to bake a 9-inch thick-crust meat pizza placed on the upper rack level. According to our accumulated data on average toaster oven performance, this deserved a 9/10.

Unfortunately, the oven lacks the high-intensity heating capability needed to crisp a crust effectively in such a short period of time, which the Toshiba AC25CEW-BS has. Consequently, parts of the crust bottom stuck to the grooves of the baking tray and the surface had a light golden color - so the score was only 5.5/10.

We had to stop baking because some of the meat and parts of the cheese started charring. It was a shame that the cheese didn’t completely melt before this, so we could only give the toppings a 6/10.

We were able to prevent the toppings from burning and the potential bitter taste. However, the crust and the topping weren’t good enough for the taste of the pizza to get a score higher than 5.5/10 from our chef.

Mueller 4 Slice Toaster Oven Pizza Test
 Mueller 4 Slice Toaster Oven PizzaA toaster oven baked 9-inch thick-crust meat pizza with cheese, onions, and green bell peppers on top inside a baking pan.
Two slices of oven baked 9-inch thick-crust meat pizza with cheese, onions, and green bell peppers on top of one another.
Two hands break apart a slice of pizza with cheese, meat, onions, and green bell peppers on top baked using a toaster oven.
Cooking Time: 6
20% * 6 = 1.2
Crust: 8
20% * 8 = 1.6
Toppings: 8
30% * 8 = 2.4
Taste: 8
30% * 8 = 2.4
  • Function: Toast
  • Temperature: 450°F
  • Cooking Time: 9m
  • Convection: No

For its low power draw, the Mueller did pretty well in our Pizza test with a score of 7.6/10.

The oven took 9 minutes to bake a 9-inch thick-crust meat pizza which was slightly faster than the label’s recommended 10 minutes. However, compared to our tested toaster ovens, it could only be a 6/10.

The crust had a golden color all the way through and the inside was still moist. If only the crust was a bit more crispy, it would’ve gotten higher than an 8/10.

The toppings were also caramelized quite evenly from the meat and veggies to the cheese, worthy of another 8/10. The cheese was nicely melted but the areas closer to the back of the cooking chamber were more caramelized compared to the rest.

With both the crust and the toppings being 8/10, our chef had no reason to give the pizza one final 8/10 for taste.

8.1

Whole Roasted Chicken

7.0
Oster French Door Toaster Whole Roasted Chicken Test
A whole roasted chicken using a toaster oven on a white background. The chicken is belly up on a baking rack with a silver baking pan below.
A whole chicken roasted using a toaster oven on a baking rack with a silver baking pan below. The thermometer displays the same temperature of 181°F from two probes inserted into the right and left thighs of the chicken.
The roasted chicken is carved into ten pieces on a baking rack with a silver baking pan below. There are three pieces of the carcass, two wings, two thighs, two breast pieces, one drumstick, and two fallen leg bones.
Two hands pulling apart a juicy chicken thigh roasted in a toaster oven. In the white background is the rest of the roasted chicken on a baking rack with a silver baking pan below.
Cooking Time: 7
20% * 7 = 1.4
Skin: 7.5
20% * 7.5 = 1.5
Doneness: 9.8
20% * 9.8 = 2.0
Taste: 8
40% * 8 = 3.2
  • Function: Turbo Convection
  • Temperature: 350°F
  • Cooking Time: 1h 10m
  • Convection: Yes

The spacious interior of the Oster seemed a key factor in our Whole Roasted Chicken test, scoring an impressive 8.1/10. We placed a 3 lb chicken belly-up on the upper rack level and flipped it after the first 40 minutes.

After 1 hour and 10 minutes, the skin reached an acceptable roasted color scoring a 7/10 for cooking time. Our chef surmised that further roasting wouldn’t result in better skin caramelization. Thus, we stopped roasting to avoid overcooking the meat and inadvertently lowering the total score.

The skin had an appetizing golden color, except for the sides of the two drumsticks which were a little lighter in color. Compared to other benchmark tests, the skin only crisped slightly indicating the heating elements and convection system to be less than ideal/top-of-the-range. The results were good, enough for a 7.5/10.

In conclusion, the oven maintained an ideal temperature long enough to evenly cook an entire chicken throughout. We measured the internal temperature of the chicken and it was 181°F. This was very surprising and almost spot-on with the recommended 165°F - 180°F by the USDA—thus earning a whopping 9.8/10 for doneness.

Interestingly, the meat came out so tender that the bone simply fell off as we tried to carve the chicken. If the skin was crispier, the chicken would have received a higher than 8/10 for taste.

Mueller 4 Slice Toaster Oven Whole Roasted Chicken Test
A whole roasted chicken using the Mueller MT-175 Toaster Oven backside up on a silver baking pan on a white background.
A whole roasted chicken using the Mueller MT-175 Toaster Oven belly up on a silver baking pan on a white background.
A tray of whole toaster oven roasted chicken. The thermometer has two probes inside the chicken and displays 185°F and 192°F.
Eight pieces of a carved chicken including two carcass halves, two breasts, two wings, and two thighs on a baking pan.
Two hands pulling apart a roasted chicken thigh. In the white background is the rest of the roasted chicken on a baking pan.
Cooking Time: 6
20% * 6 = 1.2
Skin: 5.5
20% * 5.5 = 1.1
Doneness: 8.7
20% * 8.7 = 1.7
Taste: 7.5
40% * 7.5 = 3.0
  • Function: Toast
  • Temperature: 350°F
  • Cooking Time: 1h 20m
  • Convection: No

The Mueller could barely fit a 3 lb chicken for our Whole Roasted Chicken test. Nonetheless, the result was quite decent at 7/10 in total. If you were to purchase this oven and use it to roast a whole chicken, we recommend cutting it open or chopping it into pieces beforehand.

We first placed the chicken backside down on the baking pan. When we slid the pan in, the top of the chicken breast grazed the upper heating element’s guard and was seared.

After the first 40 minutes, we flipped the chicken to find out that parts of the skin on the back got stuck to the baking pan. Then, when we reinsert the pan, the same problem with the breast happened to the back. Luckily, they weren’t burnt.

However, even after 1 hour and 20 minutes, most of the chicken skin still hasn’t reached a desirable color. The chicken, for the most part, looked like it was steamed and not roasted, so we gave the skin a 5.5/10.

Nonetheless, our chef decided to stop the roasting as the color wouldn’t improve anyway and to avoid overcooking the meat. This cooking time was the equivalent of a 6/10 according to our data.

With such a long cooking time, the meat had no pink spots. However, the chicken’s internal temperature was 185°F-192°F, higher than the USDA recommended 165°F-180°F. Thus, we gave it an 8.7/ for doneness.

While not the most appetizing looking, the meat was very juicy. That, combined with the slight caramelization on the skin, was enough for a 7.5/10 for taste from our chef.

4.1

Baked French Fries

3.6
Oster French Door Toaster Baked French Fries Test
Pieces of baked french fries using a toaster oven inside a silver grooved baking pan on a white background.
A closeup of pieces of baked french fries using a toaster oven inside a silver grooved baking pan.
Pieces of baked french fries using a toaster oven. Eight pieces of broken-up fries are stacked on top of pieces of whole fries inside a silver grooved baking pan.
Cooking Time: 0
20% * 0 = 0.0
Color: 5
20% * 5 = 1.0
Texture: 5.5
20% * 5.5 = 1.1
Taste: 5
40% * 5 = 2.0
  • Function: Turbo Convection
  • Temperature: 400°F
  • Cooking Time: 30 m
  • Convection: Yes

For our Baked French Fries test, the Oster was disappointing, scoring only 4.1/10. Our reasoning was the poor size ratio of the cooking chamber to the oven’s power output. The oven wasn’t able to maintain a high enough temperature for baking frozen fries, as opposed to the Ninja DT201.

After 30 minutes the fries showed no significant change in color—where the test time limit was 25 minutes! Therefore, we had no choice but to stop baking and give the fries a 0/10 for cooking time.

Most fries had a pale color as if they were air-dried instead of air-fried. Some small pieces had a light golden color, but that wasn’t enough to score higher than 5/10.

Texture-wise, the fries were soft but dry on the outside, barely enough for a 5.5/10. All things considered, the only silver lining was that the fries were cooked, so our chef gave them a 5/10 for taste.

Mueller 4 Slice Toaster Oven Baked French Fries Test
Mueller 4 Slice Toaster Oven Baked French FriesPieces of baked french fries using the Mueller MT-175 Toaster Oven on a grooved silver baking pan on a white background.
A close-up of pieces of baked french fries using the Mueller MT-175 Toaster Oven on a baking pan on a white background.
Ten pieces of broken-up baked french fries are stacked on top of pieces of whole fries on a grooved silver baking pan.
Cooking Time: 0
20% * 0 = 0.0
Color: 4.5
20% * 4.5 = 0.9
Texture: 4.5
20% * 4.5 = 0.9
Taste: 4.5
40% * 4.5 = 1.8
  • Function: Toast
  • Temperature: 400°F
  • Cooking Time: 27 m
  • Convection: No

Our Baked French Fries test brought out the Mueller’s weakness of not being able to maintain a high temperature due to its low power draw. Its even heat distribution couldn’t help much if the temperature wasn’t high enough, so the final score was 3.6/10.

We stopped the baking after 27 minutes as the fries weren’t getting any more colors. This, nonetheless, was over our time limit of 25 minutes, so it was a 0/10.

The fries had no significant color change and barely enough for a 4.5/10. We ended up with 12 oz of frozen fries that were more similar to being dried in an oven than being baked, so we gave them another 4.5/10 for texture.

Fortunately, the fries were cooked through and not soggy, so our chef could give them a 4.5/10 for taste and not a zero.

Aesthetic Only

Oster XL French Door Countertop Toaster Oven Design Review

Stainless Steel Mueller 4-Slice Toaster Oven Design Review: Standard
6.7
design Scores
  • Exterior (20%)8.0/10
  • Interior (30%)7.0/10
  • Build Quality (50%)6.0/10
5.3
design Scores
  • Exterior (20%)5.0/10
  • Interior (30%)1.0/10
  • Build Quality (50%)8.0/10

In the Oster TSSTTVFDDG Double-Door Convection Toaster Oven Box

In the Mueller MT-175 Small Toaster Oven Box
Top to bottom and left to right are a blue box, the Oster TSSTTVFDDG Toaster Oven, one baking rack, one baking rack with supports, a user manual, and a silver grooved baking pan on a white background.
  • Model: TSSTTVFDDG
  • Warranty: 1 year (US and Canada only)
  • User Manual
  • Baking Rack x 2
  • Baking Pan
  • Removable Crumb Tray

The Oster TSSTTVFDDG arrived boxed between two styrofoam brackets. The four accessories were packaged inside carton boxes and taped to the oven. While the box only has some basic information,  a complete user manual was inside.

A box, the Mueller MT-175 4-Slice Toaster Oven, a recipe booklet, a baking pan, an oven rack, a user manual, and a brochure.
  • Model: MT-175
  • Warranty: 1 year
  • User Manual
  • Baking Rack
  • Baking Pan

The Mueller toaster oven came in a basic packaging and positioned with two foam pads. The included accessories were simply duct-taped to the oven. Inside the box are also a user manual and a simple recipe booklet.

8.0

Exterior

5.0
An closed front of the Oster TSSTTVFDDG XL Digital French Door Convection Toaster Oven on a white background. The exterior is 16.75 inches long, 21.53 inches wide, and 12.79 inches high.
An closed front of the Oster TSSTTVFDDG XL Digital French Door Convection Toaster Oven on a white background. The exterior is 16.75 inches long, 21.53 inches wide, and 12.79 inches high.
The front and the right sides of a closed Oster TSSTTVFDDG XL Digital French Door Convection Toaster Oven on a white background. The control panel is in the front. The right side has air ventilation holes.
On a white background, the back and the left sides of a closed stainless steel Oster TSSTTVFDDG XL Digital French Door Convection Toaster Oven both have air ventilation holes. The back side has a black buffer.
On a white background, the top and the right sides of a closed stainless steel Oster TSSTTVFDDG XL Digital French Door Convection Toaster Oven both have air ventilation holes. The control panel is in the front.
On a white background, the bottom of a closed stainless steel Oster TSSTTVFDDG XL Digital French Door Convection Toaster Oven has four base stands and ventilation holes. The control panel is in the front.
  • Weight:
    16.8 lbs (7.6 kg)
  • Length:
    21.5" (54.7 cm)
  • Width:
    20.0" (50.7 cm)
  • Height:
    12.8" (32.5 cm)
  • Material:
    Stainless steel
  • Color:
    Silver
  • Door Handle:
    Cool-touch
  • Tray Indicators:
    No
  • Crumb Tray:
    Removable

Considering the Oster’s large size, ventilation slats on all sides are a big plus. (+3). At first glance, the most stand-out feature was the tempered glass french door with cool-touch door handles (+3).

It has a rear buffer to maintain a cool distance from the wall, but we thought it could be greater(+2). Additionally, while the oven’s leg stoppers are sturdy, they are rather small.

Our measurements of the oven’s footprints were 21.53" x 19.96" x 12.79" which matched closely with the manufacturer’s 22" x 19.5" x 13". On a side note, we weighed the oven and it was 16.75 lbs while the manufacturer stated the entire package to be 13.87 lbs.

A closed front of the stainless steel Mueller MT-175 4-Slice Toaster Oven with exterior measurements on a white background.
A closed front of the stainless steel Mueller MT-175 4-Slice Toaster Oven with exterior measurements on a white background.
Mueller 4 Slice Toaster Oven ExteriorThe front of a closed stainless steel Mueller MT-175 4-Slice Toaster Oven has a control panel and the right has holes.
The back and left sides of the Instant Omni Plus 18L have air ventilation holes. The back has a power cord and two buffers.
The top, front, and right sides of the Black+Decker TO1760SS 4-Slice Natural Convection Toaster Oven on a white background.
On a white background, the bottom of the Mueller MT-175 Toaster Oven has a detachable crumb tray, four stands, and holes.
The detached crumb tray of the stainless steel Black+Decker TO1760SS 4-Slice Countertop Toaster Oven on a white background.
  • Weight:
    9.0 lbs (4.1 kg)
  • Length:
    15.0" (38.0 cm)
  • Width:
    11.6" (29.5 cm)
  • Height:
    8.9" (22.5 cm)
  • Material:
    Stainless steel
  • Color:
    Gray
  • Door Handle:
    Cool-touch
  • Tray Indicators:
    No
  • Crumb Tray:
    Detachable

As simple as it is, the Mueller has all the standard exterior features of a small toaster oven but also something more. The bottom of the oven acts as a detachable crumb tray which not only makes it easy to remove the falling bits and crumbs but also to clean the entire interior.

The oven has a cool-touch door handle and back buffers to prevent it from being too close to the wall. Unfortunately, it has no cord storage or carrying handles.

Our measurements of the oven’s footprint were 14.96" x 11.61" x 8.86" which pretty much coincided with the manufacturer’s 14.84" x 11.85" x 8.86". However, the weight of the oven by itself was already 9 lbs whereas the label said the entire box was 7.63 lbs.

Control Panel

Control Panel of the Small Mueller MT-175
The control panel of the Oster TSSTTVFDDG Toaster Oven has an LCD and 15 flat buttons for Toast, Bake, Broil, Turbo Convection, Pizza, Warm, Defrost, Dehydrate, Timer, Temp, Clock, Stop/Cancel, and Start.
  • Type:
    LCD + 15 buttons
  • Temperature:
    150°F - 450°F
  • Timer:
    1 minute - 6 hours
  • Indicator Light:
    No
  • Status Bar:
    No
  • Light Toggle:
    No
  • Convection Toggle:
    No
  • Rotation Toggle:
    No
  • Automatic Preheat:
    Yes
  • Audio Cues:
    No

The Oster has an LCD and 15 flat buttons including 8 for functions, 2 for timer adjustment, 2 for temperature adjustment, a Clock button, a Stop/Cancel button, and a Start button. The oven has an automatic interior light with no toggle button.

The control panel of the Black+Decker TO1760SS 4-Slice Toaster Oven has 3 control knobs for temperature, function, and timer.
  • Type:
    3 control knobs
  • Temperature:
    150°F - 450°F
  • Timer:
    1 minute - 30 minutes + stay-on
  • Indicator Light:
    Yes
  • Status Bar:
    No
  • Light Toggle:
    No
  • Convection Toggle:
    No
  • Rotation Toggle:
    No
  • Automatic Preheat:
    No
  • Audio Cues:
    No

The Mueller has a basic analog control panel with three dials for temperature, function, and time. The time dial has a stay-on setting to help with its short range, similar to many other small toaster ovens. Interestingly, while the max temperature setting was 450°F, we actually recorded the internal temperature of the oven reaching 500°F on the said setting.

Cooking Functions of the Oster XL Digital Convection Toaster Oven

Cooking Functions
The eight cooking functions of the Oster TSSTTVFDDG Toaster Oven are in the center of the control panel. They include Toast, Bake, Broil, Turbo Convection, Pizza, Warm, Defrost, and Dehydrate. The oven’s right side has air ventilation holes.
  • Toast (level 1-6)
  • Bake (150°F-450°F)
  • Turbo Convection (150°F-450°F)
  • Broil (450°F)
  • Pizza (400°F)
  • Warm (150°F)
  • Defrost (150°F)
  • Dehydrate (150°F)

The Oster has eight cooking functions including Toast, Bake, Broil, Pizza, Warm, Defrost, Dehydrate, and Turbo Convection. Despite the name, Turbo Convection is basically Convection Bake—meaning this oven only has one convection level.

The standard Bake function and ‘Turbo’ Convection operate in the oven’s maximum temperature range, between 150°F to 450°F. The Toast function has 6 preset levels from Light to Dark, Meanwhile, the Pizza function is set to 400°F and Broil to 450°F—meaning neither can be adjusted.

The user manual recommends not to preheat the oven when using Defrost and Dehydrate. These two functions are set to 150°F—the lowest possible temperature —and cannot be adjusted. However, 150°F is a bit high compared to common dehydrators which operate at around 100°F.

For some reason, we couldn’t find the set temperature for Warm in the manual, but we measured the temperature to be 150°F.

The function dial of the Black+Decker TO1760SS 4-Slice Toaster Oven has 3 cooking functions including Bake, Broil, and Toast.
  • Toast
  • Bake
  • Broil
  • Keep warm

Different from most other toaster ovens, the Mueller’s Bake function only uses the lower heating elements as opposed to lower and upper. The Broil function still uses only the upper heating elements.

The Toast function is where both the lower and upper heating elements work. Nonetheless, the oven still provides all the basic functions for its intended purposes.

7.0

Interior

1.0
The cooking chamber of the Oster TSSTTVFDDG Toaster Oven has one nichrome heating element on top and two on the bottom, two rack levels, a shining light, and a fan cavity on the right wall.
The cooking chamber of the Oster TSSTTVFDDG Toaster Oven has one nichrome heating element on top and two on the bottom, two rack levels, a shining light, and a fan cavity on the right wall.
The cooking chamber of the Oster TSSTTVFDDG Toaster Oven has one bent nichrome heating element on top and two straight ones on the bottom, two rack levels, a light, and a fan cavity on the right wall.
Two assembled guide rails on the right side of the Oster TSSTTVFDDG XL Digital French Door Convection Toaster Oven’s cooking chamber. A fan cavity is in between the two rails.
  • Heating Elements:
    3 nichrome
  • Convection Fan:
    Yes
  • Lighting:
    Yes
  • Tray Levels:
    2
  • Rotisserie:
    No
  • Safety Hook:
    No

The Oster uses three nichrome heating elements with an unusual looped design for the upper heating element (+3). Most similar large-capacity ovens we have examined have four upper heating elements, two bottom heating elements, and a combined power draw of 1800 W.

However, the Oster has only one upper heating element which bends across and around the cooking chamber’s ceiling to cover the same area as would four. Since the power draw is divided equally between working heating elements, we speculated this design choice was to accommodate the oven’s lower power draw of 1500 W.

The TSSTTVFDDG claims to have ‘easy clean interior walls’. While they are not grease-proof, our cleaning test showed that the oven was, indeed, easy to clean (+1).

The convection fan is situated on the right side of the cooking chamber (+2). While the oven has an interior light, it’s fully automatic with no manual operation (+2).

Having only two rack levels, the oven doesn’t really require guides on the glass door (-1). The manual recommends using the upper rack position for toast and pizza, and the lower one for other foods. It’s worth noting that the rack guide rails are assembled parts and not hollowed out of the cooking chamber’s walls like many other toaster ovens.

The baking rack should not be slid into the lower rack slot with the baking tray attached to the bottom. This will result in direct contact with the bottom heating elements.

Mueller 4 Slice Toaster Oven InteriorThe Mueller MT-175 4-Slice Toaster Oven’s cooking chamber has 2 quartz heating elements with guards and 2 guide rails.
Mueller 4 Slice Toaster Oven InteriorThe Mueller MT-175 4-Slice Toaster Oven’s cooking chamber has 2 quartz heating elements with guards and 2 guide rails.
The Mueller MT-175 Oven has 1 bottom heating element with a guard and 2 guide rails on its right cooking chamber wall.
  • Heating Elements:
    2 quartz
  • Convection Fan:
    No
  • Lighting:
    No
  • Tray Levels:
    2
  • Rotisserie:
    No
  • Safety Hook:
    No

Similar to many other small toaster ovens, including the Comfee CFO-BB101, the Mueller lacks a convection fan and an interior light. In addition, it only has two heating elements which can usually lead to uneven heat distribution compared to four or more heating elements.

These heating elements are made of quartz which uses infrared light to cook foods faster than the more common nichrome counterparts. Quartz heating elements also cool down faster, are more energy-efficient and easier to clean but not as durable.

However, if grease splashes onto the heating elements while cooking, it’ll leave permanent stains. This is why they usually have guards which this oven also has.

Capacity of the Oster Double Door Oven

Capacity of the Mueller 4-Slice Toaster Oven
An opened front of the Oster TSSTTVFDDG XL Digital French Door Convection Toaster Oven on a white background. The cooking chamber is 15.75 inches long, 16.53 inches wide, and 10.04 inches high.
  • Length:
    15.8" (40.0 cm)
  • Width:
    16.5" (42.0 cm)
  • Height:
    10.0" (25.5 cm)

According to the manufacturer, the TSSTTVFDDG can take 14 slices of toast and two 16-inch pizzas on its two racks. However, our hands-on testing proved it fits only 12 slices (6 per rack, each requiring at least 4.5 x 4.5 inches of space)  or a 15-inch pizza. While it wasn’t clear what the maximum size for a whole chicken was, our tests indicated plenty of room for a 3 lb bird.

The manufacturer doesn’t state the interior capacity, but we measured the cooking chamber volume to be around 42.83 liters—our biggest number to date. However, we felt only two rack slots didn’t do justice to the oven’s capacity.

An opened front of the stainless steel Mueller MT-175 4-Slice Toaster Oven with interior measurements on a white background.
  • Length:
    10.6" (27.0 cm)
  • Width:
    9.8" (25.0 cm)
  • Height:
    7.5" (19.0 cm)

We could fit four slices of toast, a 9-inch pizza but we could barely fit a 3 lb chicken inside the Mueller, unlike the same-sized Breville BOV450XL. We measured the cooking chamber volume to be around 12.81 liters, slightly different than the manufacturer’s provided capacity of 11.67 liters. However, it could just be a difference in measuring standards.

Power Cord

A two-pronged plug power cord. In the background is the Oster TSSTTVFDDG XL Digital French Door Convection Toaster Oven.
  • Length:
    25.8" (65.5 cm)
  • Type:
    2-prong plug
  • Power:
    1500 W
  • Rated Output:
    120 V ~ 60 Hz

The power cord is 25.79" long which is enough for household use. However, it could be a bit longer since a toaster oven as large as the Oster requires at least 5 inches of clear space on all sides. The oven doesn’t have storage space for the cord like some ovens do.

A two-pronged plug power cord. In the background is the stainless steel Mueller MT-175 4-Slice Countertop Toaster Oven.
  • Length:
    30.7" (78.0 cm)
  • Type:
    2-prong plug
  • Power:
    1100 W
  • Rated Output:
    120 V ~ 60 Hz

The power cord is 30.7 inches long, suitable for household use. Unfortunately, the oven doesn’t have any storage space for it.

Baking Rack x 2

Accessories

Baking Rack
A stainless steel baking rack with two supports below of the Oster TSSTTVFDDG XL Digital French Door Convection Toaster Oven on a white background.
A stainless steel baking rack with two supports below of the Oster TSSTTVFDDG XL Digital French Door Convection Toaster Oven on a white background.
A stainless steel baking rack of the Oster TSSTTVFDDG XL Digital French Door Convection Toaster Oven on a white background.
  • Length:
    15.7" (39.8 cm)
  • Width:
    16.1" (41.0 cm)
  • Height:
    0.7" (1.8 cm)
  • Material:
    Stainless steel
  • Dishwasher Safe:
    Yes

The Oster has two slightly different baking racks. One is the standard rack type, while the other has two supports below to slide the baking pan under.

A stainless steel baking rack of the Mueller MT-175 4-Slice Countertop Toaster Oven on a white background.
  • Length:
    10.5" (26.7 cm)
  • Width:
    8.8" (22.4 cm)
  • Height:
    0.5" (1.3 cm)
  • Material:
    Stainless steel
  • Dishwasher Safe:
    Yes

The two sides of the baking rack have slight curves upward at an angle to keep the baking pan in place. It fits perfectly with the guide to help prevent accidents when placing your food in the oven.

Baking Pan

Accessories

Baking Pan
A silver baking pan of the Oster TSSTTVFDDG XL Digital French Door Convection Toaster Oven on a white background.
  • Length:
    14.13
  • Width:
    11.8" (30.0 cm)
  • Height:
    1.1" (2.9 cm)
  • Material:
    Stainless steel
  • Dishwasher Safe:
    Not advisable

The baking pan has ridges and grooves for creating attractive roast markings and catching drippings. It also has wide edges for a firm fit on the baking rack supports, unlike some other designs we’ve seen.

However, it’s not big enough to fit into the rack rail guides and can only go on top of a rack or attached beneath. This means it doesn’t make full use of the oven’s capacity. In addition, the tray is coated, but not completely non-stick so prone to stubborn stains.

A grooved silver baking pan of the stainless steel Mueller MT-175 4-Slice Countertop Toaster Oven on a white background.
  • Length:
    10.2" (25.8 cm)
  • Width:
    7.9" (20.0 cm)
  • Height:
    0.6" (1.5 cm)
  • Material:
    Stainless steel
  • Dishwasher Safe:
    Yes

The baking pan doesn’t fit into the guide rails and has to on top of the rack. This may prevent the full use of the oven’s capacity and lead to some inconveniences during cooking.

On the bright side, the pan has ridges and grooves to give your food attractive roasting marks and catch the dripping better. It has a coating but is not completely non-stick so you may need to watch out for some stubborn stains after a hefty roast.

Removable Crumb Tray

Accessories

A stainless steel removable crumb tray of the Oster TSSTTVFDDG XL Digital French Door Convection Toaster Oven on a white background.
  • Length:
    15.7" (39.8 cm)
  • Width:
    12.5" (31.8 cm)
  • Height:
    0.8" (1.9 cm)
  • Material:
    Stainless steel
  • Dishwasher Safe:
    Not advisable

A crumb tray is always a useful accessory to clean up pesky debris, especially with a large toaster oven like the Oster. Look out for crumbs falling onto the oven floor as you take out the tray. It’s quite a hassle to tilt the oven to get them out.

6.0

Build Quality

8.0
An opened Oster TSSTTVFDDG XL Digital French Door Toaster Oven on a white background. Inside the cooking chamber, from the bottom up are one removable crumb tray, one baking rack, and one baking pan under another baking rack.

The TSSTTVFDDG is light for its size and has a graspable rectangular shape making it easy to carry or position on a counter (+2). It also has a sturdy build and durable stainless steel casing (+4). The LCD is black while the numbers are yellow and the settings are red, making everything easy to see (+1).

Unfortunately,  we found that the flat buttons often required some force to register (-1). Moreover, the door hinge could be firmer thus preventing the door from slamming shut.

The front of an opened stainless steel Mueller MT-175 4-Slice Countertop Toaster Oven with an oven rack and baking pan.

For a simple small toaster oven, build quality is all about how durable it is and if it works properly. The Mueller accomplishes that with a sturdy stainless steel casing and smooth-turning dials.

Could Be Improved

Oster TSSTTVFDDG Digital French Door Toaster Oven Usability

Muller 4-Slice Toaster Oven Usability: Easy but Not Convenient to Use
6.4
usability Scores
  • User Control (30%)8.0/10
  • Oster French Door Toaster Oven Ease of Use (50%)5.0/10
  • Cleanability (20%)7.5/10
5.2
usability Scores
  • User Control (30%)6.0/10
  • Ease of Use (50%)4.0/10
  • Cleanability (20%)7.0/10
8.0

User Control

6.0

The Oster’s controls are easy to understand since what you see is what you get (+2). Therefore, the LCD doesn’t provide any extra information but it’s easy to read (+2).

The buttons have only a single function and are easy to tell apart(+2). Although the manual says you can press the Stop/Cancel button twice to turn off the oven, we weren’t able to do so (-1).

The temperature can be adjusted in increments of 5°F and the timer runs from one minute to six hours, which is quite impressive (+1). Time can be adjusted in increments of 1 minute up to  2 hours and in increments of 0.5 hours above 2 hours (+1).

To set up the clock, press the clock button once and the clock will flash. Then, use the arrow keys to set the hour and press the clock button again to likewise set the minutes. Finally, push the clock button or the start button to set the time (+1).

Even though the Mueller only has three simple control dials, there are a few things to keep in mind. For the timer knob, when setting it to less than 10 minutes, always rotate past 10 minutes and then rotate back to the desired time.

It’s always tricky to precisely adjust time and temperature for an analog-control toaster oven and this one is no different. Nonetheless, you can use an external timer and an oven thermometer to get more accurate readings.

If you frequently use the stay-on feature, you can turn off the oven by rotating the function dial to Off instead of the timer.

5.0

Oster French Door Toaster Oven Ease of Use

Ease of Use

As you select a function, the corresponding icons will illuminate in the LCD screen. The TSSTTVFDDG has an automatic preheat phase which is only applicable for the Bake and Turbo Convection Bake functions (+1).

After setting the time and temperature, you then push start and the display will show PrE indicating the oven is in the preheating phase. You can bypass this phase by pressing the start button a second time.

Preheating takes roughly 5 minutes to around 300°F regardless of the  temperature you set. You can readjust the time and temperature only after the preheating phase.

Interestingly, we found that the oven would return to preheat mode after adjusting the temperature until the new input temperature was reached and not just 300°F. This is also stated in the user manual.

The racks fit perfectly into the rail guides thus preventing accidents when placing food in the oven (+3). When the cooking cycle begins, the interior light will turn on automatically and then off when the cooking cycle ends (+2).

The french door and its cool-touch handle allow you to stay away from the heat wave when opening after cooking (+4). The doors are also single-pull which is very convenient. However, the doors cannot open partially and can slam shut if your hand slips (-2).

Unlike some ovens, opening the door doesn’t stop the oven or the interior light (-2). The oven casing can get very hot after long cooking times at high temperatures, so you should take care (-1).

When the cooking cycle finishes, the oven will beep once, switch off the heat, and return to the clock screen. It’s advised to unplug the oven after use.

What’s convenient about 100% analog toaster ovens is that it’s very simple to adjust time and temperature during cooking. When the timer runs out, a bell will sound and the oven will shut off. Afterward, you can freely leave it plugged in and not worry about power consumption as it has no digital display.

The door can open at any angle < 50° to let food cool down inside the oven. However, keep in mind that opening the door doesn’t stop the oven. The exterior shell isn’t very thick, so it gets hot to the touch quite quickly during cooking.

7.5

Cleanability

7.0
A silver baking pan of the Oster TSSTTVFDDG XL Digital French Door Convection Toaster Oven with some stains on it on a white background.

The stainless steel exterior of the Oster was very easy to clean (+2). Even though the interior doesn’t have a non-stick coating, there are no tricky nooks and crannies, so cleaning didn’t require much labor (+4).

After roasting a chicken, the baking pan accumulated some stubborn stains which we were able to remove even with a baking soda paste and water (+1.5). We were worried the grease could splash inside the fan cavity while cooking, but this was not the case.

Mueller 4 Slice Toaster Oven CleanabilityPermanent stains on the left cooking chamber’s ceiling and the upper heating element’s guard of the Mueller MT-175 Oven.
Mueller 4 Slice Toaster Oven CleanabilityPermanent stains on the left cooking chamber’s ceiling and the upper heating element’s guard of the Mueller MT-175 Oven.
Permanent stains on the right cooking chamber’s ceiling and the upper heating element’s guard of the Mueller MT-175 Oven.
The cleaned grooved silver baking pan of the stainless steel Mueller MT-175 4-Slice Countertop Toaster Oven.

We clean the stainless steel exterior with no problem. However, after the chicken test, there were burnt bits stuck to the upper heating element’s guard and grease on the cooking chamber’s ceiling. There was ample space between the ceiling and the upper heating element, so we proceed to try every cleaning method possible.

Unfortunately, we could only scrub off the bits. Due to the interior not having a non-stick coating, there were some permanent stains on the cooking chamber’s ceiling and the upper heating element’s guard.

Luckily, the heating element itself was intact. Also, we were able to remove the stubborn stains on the baking pan by brushing them with a paste of baking soda and water.