The Fresh Loaf

News & Information for Amateur Bakers and Artisan Bread Enthusiasts

"reversed" proofing box

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MoonshineSG's picture
MoonshineSG

"reversed" proofing box

While most people need a warmer environment to ferment & proof the breads,  when outside temperature are, year long, around 30C (86F) a cooler place is what is needed.  A styrofoam box and a peltier module were the base of my project.  After using the "cooler box" my dough seams to have more strength and the bread a much nicer oven spring and blooming...  Here are some pictures. If anyone has wants to buld a similar box and needs a few answers, I'd be glad to provide answers (if I have them)

 

1. the components (the little white square in the middle is the main character. the rest - supporting actors)

2. proof of concept. It works!!! (red temperature is the enclosure, the black is the cooling element)

3. everything put together in a custom cut acrylic box fixed on top of a large styrofoam box

4. the inside of the styrofoam box

5. final product

6. final product in "production" (variations of +/- 1C from the set temperature)

7. the box can fit about 8 bannetons on 2 layers ...

8. ... or 2 custom cut proofing boards (2 layers)

 

 

It was fun building it, lots of fun using it!!!!

Doc.Dough's picture
Doc.Dough

How about a parts list with your sources?

It is bigger than a personal refrigerator, holds enough dough for a family, and should work in anyplace that has reliable power.

How long does it take to cool down and stabilize with your normal load?

MoonshineSG's picture
MoonshineSG

The list of components and sources:

- 231W 15.4V/15A Peltier module - ebay (china)

- 15V/15A power source - local electronics shop - one of the most expensive parts of the whole project

- 12V power source - local electronics shop - a wall charger with removed cover

- DC/DC Solid State Relay - local electronics shop - second most expensive part

- heat sink with fan for SSR - local electronics shop

- 2 x12” fans (Scythe Gentle Typhoon) - local computer shop

- heat sink for peltier module - local computer shop - any CPU heat sink will do. Some come with fan so you don’t need to get two (above)

- aluminium heat sink (for the cold part of the Peltier module) - ebay (HK)- 30cm x14cm (cut to 14x14cm)

- temperature sensor - ebay (HK)

- peltier module controller - ebay (China)

- Arctic MX4 thermal paste - local computer shop 

- mica plates for thermal insulation - ebay (HK)

- power switch, plug and cord - local electronics shop

- custom plexiglas box, rubber gasket, internal plexiglas shelve and wooden proofing boards - local laser cutting shop based on my own specifications

- styrofoam box - local fishing shop

- wires and screws - local electronics shop

I have not indicate the prices as those might vary form shop to shop. I spent around US$200 (!!).  I know that is not a cheap thing to build, but I couldn't think of any alternative.  The good thing is that the impact on my brad quality is huge.  Before this, with the exception of ciabbata, anything else was barely acceptable. Once I started using the box,  my bread has a much more opened crumb and the oven spring has probably doubled... Now baguettes are like baguettes should be!

As I use a relatively powerful Peltier module (231W) the initial cooling time is around 20-30 min and it takes less than 15 min to stabilise once I put in my dough (either for fermentation in a bowl or shaped for proofing) 

Probably I could have use a smaller box (with a smaller Peltier module and a cheaper power source) for daily use, but occasionally I intend to bake for friends/party so that would require larger quantities of dough to be prepared. 

 

 

rossnroller's picture
rossnroller

My place of residence, Perth, Western Australia, is not as warm as Singapore year-round, but much hotter during a lot of the summer. It's a muggy 35C or so today, and we have just had a heatwave where it was 40C+ for days on end (felt like weeks). This can go on well into March, and even in April we can get mid-30s days. So, for several months per year bread making is not terribly easy or pleasant.

I made a SD bread on one of the 40C days last week, and it was 35C in the kitchen during the bulk proof (at night!). I had to reduce the BP to 1.5 hours (next time at these temps, I'll reduce it still further to 1 hour!),  and retard in the fridge immediately after shaping, and it was still a bit wonky - somewhat overproofed, but also with some signs of gluten underdevelopment! Still tasted nice, but not as good as in more moderate bulk-proof temps. At 35C+ I just don't think our yeastie friends function all that well. Can't say I blame them!

I have often wondered about a "reversed" proofing box for summer, and yours is the first I've come across. I'm not confident enough with the technicals to put one together for myself, unfortunately, so I'll just have to struggle through on the very hot days, making whatever adjustments I can. I've thought of experimenting with doing the entire BP in the fridge, as well as the FP, but have been loathe to go ahead with this because I hate the thought of  having to toss the dough due to a failed experiment. Adventurous, aren't I?

Anyway, good on ya for putting your electrical and technical knowledge to such good effect as a baker! I'm envious.

Cheers!
Ross

Doc.Dough's picture
Doc.Dough

Thanks for the detail. That gives me something to work from.  It is a big Peltier module, but you need it to get the initial cooldown.  You could probably use a 20 amp automotive battery charger as a power supply since the Peltier doesn't care much about ripple and everything else is running on regulated 12V.  Might be less expensive, but maybe not, depends on what you can find in the garage, the junk box, and at the local swap meet.

One more question - is the controller a PID type or just bang/bang on thresholded temp sensor output with or without hysteresis?

MoonshineSG's picture
MoonshineSG

The controller is a on/off type. This is the exact model

Justin's picture
Justin

That looks really cool! I've been thinking about making a peltier controlled proofing box for a while now. I'd like to have arduino controlled heating/cooling so that I can do an overnight/at work retardation at fridge temperature, and then a timed increase to the actual proofing temp, so that the dough will be (almost) ready to bake when I get back from work/wake up.

What's the lowest temperature you can get down to? Given some reasonable room temperature (i live in the UK so it won't be as high as yours)

MoonshineSG's picture
MoonshineSG

Although the specs for the peltier module show a ΔT of 70C, I never managed to get below 7C. That could because of many reasons. From the position of the sensor - which would mean that the peltier get colder but I measure it slightly off, to the inability to cool the heat sink fast enough,  or the rate at which the cooling sink absorbs the heat from the box and the fact that the box is not 100% insulated. 

That being said, I managed to the the box cooled to about 15C which is not enough for "retardation at fridge temperature" (about 5C).Even to get to those temperature takes quite long.

Having the same box doing the retarding and the roofing might prove to raise the problem of calculating the time requirements. You'll need to determine the speed at which your box warms up, or add a heating element as well to bring the temperature from 5C to 21C in a mater of minutes not hours (as it would probably happen in the absence of a heating element) . 

Good luck, and let us know if you managed to work it out.

 

PS Having the system controlled by a arduino is a very sexy idea, but beyond my needs.... And yet... :D

 

 

Note: there is one issue with the box that I have not foreseen: intense condensation. As the humidity in Singapore is quite high (70-90%) the cooler element is like a broken tap. I need to find a way to capture and store all that water so it doesn't get on the dough... If used in warm but dryer environment, this might not be an issue... 

 

Justin's picture
Justin

Interesting, I hadn't really thought about condensation. Especially as I'd imagine that for the sake of the dough it would be a reasonable idea to keep the environment in the box relatively humid, so it might be a bit of a problem.

My plan was to reverse the voltage on the peltier so that it acted as a heater, rather than a cooler, to get the box back up to a proofing temperature quickly.

I guess the best approach will be to buy some bits and start experimenting!

MoonshineSG's picture
MoonshineSG

If you intend to reverse the polarity, do it at a much lower voltage as that thing get's pretty hot. Nothing more fun that doing some tests...