Experiments to raise bread machine baking temperatures
The purpose of this thread is to explore the effectiveness of some relatively simple ways to raise the baking temperature of bread making machines (BM for short), most of which bake at temps of 300ºF and below.
The guinea pig for the first experiment is an interesting machine from the turn of the century (that makes it sound really old...), the West Bend model 41099 Baker's Choice Plus. (Some quick history: Around Y2K the BM market was still dominated by Japanese companies, though most were already made in China. Panasonic and Zojirushi were the market leaders. West Bend was the only US company designing and manufacturing BM's in the US.) I got this 41099 in near-new condition at a local thrift store for $14.
The "Baker's Choice" line appears to have been West Bend's shot at the high-end of the market, specifically at Zojirushi and their very successful V20 model. The 41099 has the same slanted control panel, horizontal bread pan with dual mixing paddles, and swoopy, rounded, cream-colored plastic molded exterior as the V20.
The 41099 has a few unique features, clearly aimed at making using it similar to baking in a conventional oven.
1. An oven light. Press the top-right button on the control panel and a bright lamp lights the oven interior for 10 seconds and then shuts off. Every BM should have one of these!
2. Extended rise time. Need to give a loaf more time to rise before baking it? Pressing the Extended Rise button adds either 10 or 20 minutes to the final rise time. Your selection is indicated on the LCD display.
3. The front-opening oven door. This allows the door to be opened fully when the unit is placed under kitchen cabinets, giving easy access to the oven interior and the 9"x5"x4.5" bread pan inside.
These are useful features, especially when experimenting with recipes.
The large door does have one drawback. It is leaky. It's contact area with the oven is large and it doesn't seal well at all. Gaps around the door's perimeter set up a thermosiphon effect, pulling room-temperature air in through the bottom edge and pushing hot air out the top edge, which cools the oven more than a top-loading door does.
So how cool is it? I made a loaf using the whole wheat program and measured the bread pan temperature using an infrared thermometer. The highest it got was 282ºF. That is the lowest pan temp I've measured for any BM. And it didn't get there until near the end of its bake cycle. And, because of the low baking temps, the bake cycle is quite long: 80 minutes for a medium-crust 2 lb. loaf.
So, I think you can see, this is the perfect guinea pig for this experiment. The goal is to get temps up into the low-mid 300's. If the modifications are a success, we should have a very nice horizontal BM that is versatile and easy to use.
We'll detail the mods in the next installment.
Well I thought this was going to become an interesting, productive project, but it got nipped in the bud right away. So I'll condense this considerably.
My first idea to raise the 41099's baking temps was to reduce the leaks and insulate the oven, using Kaowool 1/4" Ceramic Fiber Insulation, which I have a roll of here. This is what it looks like; pics of the door, before and after insulating.
It's not worth showing the rest of the pics. Suffice it to say, the door and oven were thoroughly insulated and the leak gaps were closed.
The result: No change in the maximum baking temps. Why? Because its internal computer is monitoring and controlling the temperatures, changing the on/off duty cycle to regulate them. So the insulation probably made the machine more efficient (use less electricity), but the pan temps at any point in the cycle were unaffected. It still ramps up gradually and tops out at 282º 10 minutes before the end of the cycle, just like it did with the last loaf I baked in it.
Disappointing, for sure, and a pity, because this approach worked really well raising combustion temps in critical areas of woodstoves. Raising the baking temps would require reverse-engineering the builtin computer and thermal sensor circuits. Not worth it.
Moving on to idea #2: Paint the bread pan exterior black. It's well known that dark baking pans absorb more heat than shiny aluminum ones. I have high-temp black spray paint here. Thing is, given the low temps at play here, I'm doubting if it will make much difference. 282ºF max is the lowest of any BM I've measured.
So this machine will get used in the colder months to knead and rise dough for oven baking.
I welcome any thoughts you may have about this.
Not one to be deterred by failure, I decided to move forward with my second experiment, but with a bit different goal in mind. Having learned that the BM's computer is in control of baking temperatures, attention turned to another shortcoming of most bread makers: poor upper crust browning, especially when the bread pan is less than full. I see this mainly on machines with thin aluminum bread pans, which nearly ALL new BM's are using (Panasonic is the only exception I know of; they continue to provide nice thick cast aluminum bread pans with their new machines).
So the question is: can upper crust browning be improved by painting the upper part of a thin aluminum bread pan with high-temp black paint?
The guinuea pig for this experiment is another West Bend machine, model 41053 from the late 90's. I picked one up at a local thrift store in like-new condition for next to nothing. It has a horizontal pan made from thin sheet aluminum, bakes a bit hotter than the 41099 (305-308ºF), makes decent bread, and doesn't brown the upper crust well, as can be seen in this pic.
The test loaf is an Italian bread recipe with about a cup of wheat bran added. It's easier to see browning pattern on mostly-white-flour loaves. Here is the test loaf made in the unmodified bread pan.
There was a bit too much yeast in this mix (a frequent issue here at 7,000 ft.), causing the bulge in the middle. The very top of the bulge browned a little because it is closer to the top of the pan.
The upper half of the outside of the bread pan was spray-painted with Rust-Oleum High-Heat flat black paint, making sure to mask off everything else to block the overspray. After completely drying, it was baked empty at 300ºF to burn off residual odors.
The next day, another test loaf was baked. The only differences were: 1/4 tsp less yeast, and 4 minutes less bake time (my error, not intentional).
The result is a loaf with more consistent crust color top-to-bottom, despite its lower profile and slightly less bake time.
The non-stick coating inside this pan is a light gray. I think top browning would have been even better if was dark-colored. But as it is, this is a promising first result.
Here's an animated GIF that makes the before/after comparison easier: