The Fresh Loaf

News & Information for Amateur Bakers and Artisan Bread Enthusiasts

Tubs for mixing and bulk fermentation

hazimtug's picture

Tubs for mixing and bulk fermentation

Hi baker friends,

I am about to take my baking "online" by scaling up from 2 loaves a week to 10 - 12 (1.5 lb) loaves a week so that I can start selling at a local shop once a week. Hopefully, a first step towards a rewarding, pleasurable and challenging career for the future! For those curious, I will be doing this in Michigan under the Cottage Food Law, which allows to bake at your home and sell in limited quantities.

My question is regarding dough tubs. Currently, I use a big glass bowl, covered with a kitchen towel and I place it in the bread proofing box (Brod & Taylor) to control the temperature and have a more predictable bulk fermentation. Now that I am planning to bake in bigger batches, I was thinking of larger size rectangular plastic tubs for mixing and bulk fermenting. However, those tubs will not necessarily fit in the proofing box that I have, which brings me to my question.

How good are plastic tubs in maintaining the dough temperature? My house is typically around 68 - 70 F (much cooler than a bakery environment) and I would like the maintain bulk fermentation temperatures of 78 - 82 F (hence I have been using the proofing box). Will I have to use the bread proofing box (15” x 12-1/2” x 8-1/2” high) or my oven (in both cases, the size of the tubs will be limited) or some warm place in the house if I am using plastic tubs? Before I make any investments, I wanted to see if anyone has an opinion/experience on this...

Thanks much!


mini_maggie's picture

When I've done big batches the bathroom with the door shut and the thermostat turned up a few degrees becomes my proofing room - timing usually works out that it's humid in there anyway after my bath but you could always put a bit of hot water in the tub or turn the shower on for a few at the outset. 

hazimtug's picture

That sounds like a fine idea, except the bathroom is typically cold here, unfortunately... thanks Maggie!

David Esq.'s picture
David Esq.

To me, the thought of buying bread spending hours on end in someone's bathroom is a bit off putting. Even though it is one of the warmest and most convenient places closest to my kitchen, I won't put dough or starter in there because i think it is inherently unsanitary.

dosco's picture

... on how clean your bathroom is, and if the humidity in there is under control (or not).

In the end I'm not sure it matters ... if you bake at 500F then I would presume any 'bad critters' would be toast.



MisterTT's picture

but only the surface of the bread will reach such a temperature. Inside the loaf there won't be but 95 C.

David Esq.'s picture
David Esq.

By that logic you can poop in the baker's oven and it would all be okay. And it might be, just not for me. 

dosco's picture

By your logic, merely walking into the bathroom would result in immediate infection with various fecal-borne pathogens.

(I assuming that because you haven't died of hepatitis or dysentery that this is not the case).

With that said I'm not advocating that one prepares or consumes food in a bathroom, nor would I ever condone something like that when discussing commercial preparation of foods. I think it's rather obvious that the various and sundry licensing authorities wouldn't take kindly to such a process.

Sorry for upsetting the apple cart!!



mini_maggie's picture

A. My bathroom is very clean

B. The dough is in covered containers and not around the toilet or sink

C. No one uses the toilet in that bathroom while dough is proofing - the main bathroom downstairs gets the traffic. 

I was not suggesting someone perch dough in a dirty bathroom or near a toilet in use...  But I would assume that just goes without saying.

David Esq.'s picture
David Esq.

Indeed. I was just saying I wouldn't knowingly eat food prepared in a bathroom. And as such I would not prepare food for someone in a bathroom.  that people feel otherwise just makes me happy I don't buy food from people  who cook at home. 

OldWoodenSpoon's picture

insulating value and will tend toward ambient temperature.  I am talking here about the typical bus tubs and Cambro tubs readily available through foodservice outlets.  That means that if you want to control dough temperature to some range other than ambient you should plan on using some kind of proofing enclosure.  The Bod & Taylor is probably not big enough to handle more than about a 4 loaf batch due to it's limited (by size) heating power.  It's also, as you note, just not big enough physically.  There are some very creative ways to make a proofing box larger than the B&T, and many of those are discussed in some detail here on TFL.  Just type "proofing box" in the search box above and you can find those discussions pretty easily.

Good luck with your venture!

PatrickS's picture

If I was going for a big space for proofing, I would make up a big plywood box and put one or two of these in it:

Bob S.'s picture
Bob S.

Food grade plastic pails are inexpensive and should ferment dough well (as long as the ambient temperature does not dip too low). A 5 gallon pail should handle the amount of dough you are contemplating using. Here is a link:

Alvaremj's picture

I feel the simplest answer is to bulk rise at room temp for longer time, or adjust amount of preferment to shorten time and adjust to your schedule. I do a bulk rise overnight in the fridge (after 2 hrs on counter) and proof on counter at about 68 degrees.

good luck


hazimtug's picture

Thanks all... I appreciate the responses. Not having to worry about finding a warm place/environment for the bulk fermentation seems like the easiest/most convenient way to go, yet it calls for more experimentation... I would also be curious to see how the flavors would change as well. I'd imagine the loaves would taste somewhat more acidic than lactic that would be achieved at higher temperatures. I'll give this option a try to see if/how I can adjust to the challenges ;). As always, thanks again for all the insight!



Mark Sealey's picture
Mark Sealey


The 6 quart Cambro tub with lid fits nicely inside the Brod and Taylor Proofing Box. They work very well together. Good luck!

clazar123's picture

There is so much wrong with even typing that statement no matter how clean your bathroom is. There is a reason why that activity is separated from food prep. If you have ANY oversight from licensing, that would be a HUGE violation and rightly so.

Many good ideas for a proper way to bulk ferment and there have been very many unique inventions and ideas on how to make a larger proofer at home. Take a walk through the "Search" box. Some are very inventive.'s picture

When our house temperatures descend to those of a retarder (<=60˚F [15˚C]) this time of year) rather than those of a proofer (=summer), I run warm water into a stoppered kitchen sink and set my dough tub in it with the water up to level of dough.  Needless to say, this speeds the bulk along about as fast as you're willing to warm the water, up to a max of ~95˚F (35˚C).  I have a home-made styrofoam proofer for proofing in brotforms/bannetons this time of year, but rarely use it because top 'o the hot water heater proofs doughs fast enough and I don't proof more than a couple at a time.

Nice loaf in your picture btw.


Frequent Flyer's picture
Frequent Flyer located in a small closet.  I find the temperature in the closet is about 10 F above our home temperature.  That's a good proofing environment for my breads.


LostHighway's picture

A few strains of brewing yeast like quite high temperatures, as high as 90F/32C.  Among the tricks to achieve that are to buy a large chest cooler and keep the fermenters in a warm water bath.  The crudest system is entirely manual, siphon out cooling water and add warmer water as needed, but that requires way too much attention.  A step more sophisticated is to use aquarium heaters to maintain water temp. If you want really precise control you can use a PID (proportional-integral-derivative) controllers connected to a thermal probe in the dough itself and a heating element.

I don't know enough about bread making (yet) to know if this also applies to bread but in beer brewing changes in temperature during fermentation can alter the flavor profile of the finished product.  Sometimes as little as 5 degrees F or 3C can produce a subtle but noticeable difference. Brewers sometimes alter the temperature at different stages of the process to achieve the results they desire  I would suspect (hypothesize?) that in the more complex ecology of sourdough cultures this might be even more the case. FWIW some beer styles also use complex cultures containing Lactobacillus, Pediococcus and Brettanomyces in addition to good old S. cerevisiae while others simply use wild airborne yeasts and bacteria.

Atropine's picture

:D  I cannot agree more with the idea of NOT proofing in a bathroom.  Even if you scrub your bathroom every.  single.  day.  with bleach, as soon as someone flushes their constitutional, that is aerosolized and descends on every surface (they have done some studies on that.).  Our bodies are relatively used to the germs in our house, so we can brush our teeth with the toothbrush that is sitting by the toilet without thought (except in the case of a few germs that are hard to build up a resistance to).  However, someone ELSE whose immune system is used to a different set of germs might get sick, especially if they have a weakened immune system (for example, someone who is having chemo).

Now, for us going in and out of bathrooms, our constitution can handle it.  And perhaps a sourdough could even withstand if the colony is vigorous enough to crush out the bad germs.  But seeing as how some germs can survive on glass and with some, as few as ten germ cells is enough to cause illness, I would not risk it.  We also have to consider the proofing vessel which will need to be sterilized every time as well as cross contamination from the door knobs or light switches as we take the proofing box from the bathroom to the kitchen to make the bread (which people do not often think of cleaning).

Additionally:  with some germs it is not the germ itself that causes illness (high heat does kill germs) but their toxins cause illness, of which some are not broken down by heat.

One last point regarding liability: Consider this....a cottage bread baker proofs her bread in the bathroom.  A customer buys his/her bread and gets sick a little while after eating it--NOT because of the bread but perhaps a bad salad or something that they ate the bread with.  However, the customer remembers the bread and reports it.

If the health folk come to the baker's house and the baker shows them a clean, neat set up in the kitchen for bread baking, then the baker will probably be off the hook.  If the baker has bread proofing in the bathroom, the potential for lawsuits and criminal penalties increases.  Even if they are cleared, the news will get a hold of "bathroom bread" (ugh!) and the baker might very well have to find a new job.  Also, the ramifications to the rest of the cottage food industry will be enormous....including the possibility that cottage production will be disallowed.

People who want to do cottage production (which I applaud!) should be careful to have AT LEAST as rigorous as restaurants and bakeries, not only because it is smart, but also to save themselves from lawsuits and to protect the cottage industry.  :)

Now, as for the heat issue...what about using the plastic box within a proofing box with a seed starting mat under it?  That might give you a nice, steady heat in the right range without the mess of water (though I think the idea of an aquarium heater is positively elegant)

vtsteve's picture

is to use your dishwasher as a proofer - run a hot rinse cycle, then put the tub in while it's still warm and damp. Most tubs in white (natural) plastic are food safe; I have some from Vollrath (nice and smooth inside) and Carlisle (had to smooth out some seams). I use a covered rack with an oil-filled radiator for heat, to proof three tubs @ 8.5 kg each.