Building a Homemade Proofing Box

[tino27]

With the cooler weather now returning to Ohio, I am re-contemplating the thought of building (or buying) a homemade proofing box to combat the extra long rise times that will ultimately result because of my cooler kitchen. Because I currently live in a fairly old house built in 1914, the kitchen can become quite chilly in winter (52-55 deg F) which makes for some painfully long breadmaking sessions. I've used the oven before to proof dough, but if I'm making multiple batches, only one batch at a time can occupy it. I've looked on Google for a proofing box for the home cook, but alas, I haven't found anything. Do any of you eGulleter's out there have some suggestions for a quick, easy, and cheap way to put together an effective proofing box? Or even a suggestion for a product that already exists?

[flacoman]

The simplest thing is to replace the bulb in your oven with a higher wattage (100W)

Pre- heat to 150 or so and leave the light on. Works well for drying fruit and making jerky also. Give it a shot, it's easy enough to try!

HTH

Jorge

[alanamoana]

this isn't really a proofing box, but you can probably use something similar to it, then rig up a box...

i used a plastic sheet pan turned over a heating pad (which i also use for chocolate work) on top of which, i place my proofing items. i'm sure you can just put a large plastic storage container over the top to keep the heat in. maybe add a container of hot water at the start to give you the humidity you need.

they're always selling those huge rubbermaid and sterilite storage containers (like for the garage) at a discount at target and such.

don't know if this will give you any ideas or not

[K8memphis]

You can use the microwave too. In a cold oven or in the cold microwave I put hot water in a pan under my dough. I refresh the water as necessary. Works for me. So I guess any box would work kinda sorta, but I've always managed with those two 'boxes'.

[chefpeon]

When I was a kid, my mom always made bread every Saturday. There wasn't enough room in the oven for all the bread, so she'd stick a few loaves in both bathrooms and close the door. The bright heat lamp and the steam from our recent showers made great "proofing boxes"!

We couldn't wait for the bread to rise. Not because we wanted some, but because we had to pee so bad......

[Bill44]

This is my proofing box, made out of plywood and heated by a thermostat controlled 40Watt lamp.

[fiftydollars]

I made a box using a fish heater and an ice chest. The heater is submerged in water, which encourages some moisture and the ice chest helps keep a steady temperature. It's very simple, cheap, and pretty effective.

[bigred93]

Upside down bus tub and a seed sprouting heating mat. Works like a charm.

[tino27]

Thanks everyone for the suggestions. Unfortunately, I can't use the light in my oven (regardless of the wattage) because it is a rather inexpensive oven and while it does have a light that turns on when you open the door, there is no way to keep the light on once the door is shut. I'm also digging the use of a heating pad with an inverted Cambro style food box.

Bill44 -- I'm totally in tune with what you've come up with. The only thing I was thinking of adding would be a couple of rails on the inside so that once I've shaped my freeform loaves, I could place them on a half-sheet pan and slide them into the box. One question for you though ... on the right hand side of the first picture you posted, it looks like there is a knob-type device. What is this for? And if you don't mind me asking, about how much did it cost you to put it together?

I have a friend who is totally into woodworking that would love a project like this, so I may have to trade him bread for box.

[Bill44]

Thanks everyone for the suggestions. Unfortunately, I can't use the light in my oven (regardless of the wattage) because it is a rather inexpensive oven and while it does have a light that turns on when you open the door, there is no way to keep the light on once the door is shut. I'm also digging the use of a heating pad with an inverted Cambro style food box.

Bill44 -- I'm totally in tune with what you've come up with. The only thing I was thinking of adding would be a couple of rails on the inside so that once I've shaped my freeform loaves, I could place them on a half-sheet pan and slide them into the box. One question for you though ... on the right hand side of the first picture you posted, it looks like there is a knob-type device. What is this for? And if you don't mind me asking, about how much did it cost you to put it together?

I have a friend who is totally into woodworking that would love a project like this, so I may have to trade him bread for box. 

←

The knob on the side of the box is for adjusting the temperature, the thermostat is from a chicken incubator and is accurate to +/- 1/2 degreeF which is great if you wish to do an accurate Detmold 3 stage starter. The box itself is made from scrap ply which cost me nothing and the thermostat cost me A$80.00. I think you can get cheaper thermostats from a pet store, they are used for reptile cages.

I bake 5-6 loaves a week year round, so the cost of the thermostat quickly paid for itself, and I do like the accuracy.

The size of the box is big enough to take a 11Litre dish for bulk proving, and it will take 4 oval 1Kg bannetons or 3 round 1Kg bannetons

Edited September 2, 2006 by Bill44 (log)

[andiesenji]

Here is an earlier thread on

proofing in winter

[andiesenji]

However, you can make a very inexpensive proofing box from one of the small refrigerators made for dorm rooms, etc., and which can be found at thrift stores, Goodwill and similar stores or swap meets for $10.00 and up.

They are already insulated and all you need is to drill a hole in one side through which you can thread a wire, then, mount a ceramic light fixture base over the hole on the inside and use a 40 watt bulb to heat it.

You can get the fixtures with either a chain switch which will be on the inside of the box, or an in-line switch on the cord (more desirable in my opinion).

surface mount socket

socket with in-line switch

Also drill 2 1-inch holes in the top of the fridge, at diagonal corners, to vent excess heat/moisture. A hole saw works best.

There was a web site that had this conversion diagrammed but I can't find it at the moment. However it is not all that difficult. Just remove the cord to the fridge itself and if it has and external coil, remove that also, however most nowadays do not.

You can even plug the cord into a timer so that it will turn off and on periodically to maintain the correct temp. One of the thermometers that has a probe on a cable, with a magnetic base to stick on the door is perfect for checking the temperature without opening the door.

Edited September 3, 2006 by andiesenji (log)

[RuthWells]

I use a large rectangular tupperwear box, inverted over the dough, with a bowl of hot water along side (still under the box). Low-tech, but it works.

[devlin]

I use Ed Wood's suggestion in his Classic Sourdoughs. It's super simple, and it works beautifully.

Simply buy one of those roughly 75-80 quart (or bigger, depending on what size you need) Sterilite type plastic/rubber tubs with a lid at Wal Mart or wherever, a clip-on lamp with a flexible neck, and a cheap plastic temperature guage.

Clamp the lamp to the lip of the tub, lower the neck into the tub so you can still loosely cover the tub with the lid, set the temp guage in the box about where you plan to set your stuff to proof, and voila. I use a 60-watt bulb. You can either use a towel over the lid as well if it gets really cold, or in not so cold weather you'll have to experiment a bit with how much to cover the tub.

I use it for my sourdough culture, and I usually end up covering about three quarters of the top the tub with the lid only. In exceedingly cold weather, I throw a towel over the lid as well.

No holes to drill, no box to construct, no having to juggle time in your oven for other things.

[tino27]

Well, I've decided to take a sort of hybrid approach to all of the wonderful suggestions that have been posted here and on the other thread that andiesenji pointed to.

I stopped at Wal-Mart today at lunch and picked up a Sunbeam heating pad ($25), a very large (75L maybe) translucent plastic tub ($7) and one of those stick-on aquarium temperature gauges ($3). The plan is to lay an inverted half-sheet pan over the heating pad, place the bowl of dough on top of that (or another sheet pan with shaped dough ready for final proofing), and then the tub inverted over all of that. Even though the aqarium thermometer only goes to 86 deg F, that should be plenty seeing as I am shooting for between 77 to 82 deg F. I made sure to get a tub big enough to hold either an entire half-sheet pan OR two of my workbowls (so I could be working on two batches at any given time).

I will post pictures and results tomorrow.

Note: There were cheaper heating pads available, but almost every one of them had auto-off after two hours. That and they looked a little flimsy. The Sunbeam has six heat settings, includes a continuous "on" setting, and had a 12 foot cord to boot. Fortunately I've saved my receipt in case this doesn't work.

[andiesenji]

I have used the heating pad method with excellent results. You can get a cheap but fairly accurate thermometer that is made to stick on the outside of a window (facing the glass so you can see it inside) which I have used on the inside of a big Sterilite container which fits over my long dough bowl.

The only difference is that I bought a heating pad made for dogs (puppies actually) that is 100% waterproof. (Actually I bought two, because at that time my basenji was in whelp and I needed one for the puppies too.) I still have the one I use in the kitchen - it is also handy for gently heating cream and keeping it warm over a long period of time for making clotted cream. There are a few other less common uses.

waterproof heating pad

the medium size

Edited September 5, 2006 by andiesenji (log)

[tino27]

OK, results time. I decided to test out the rig on the dough that usually gives me problems during the winter time because it is heavier than my other doughs -- the Honey Whole Wheat. I mixed up a batch, covered it with plastic wrap and placed under the plastic tub on top of the cookie sheet. I then placed the heating pad on continuous "high". I did an initial rise, a second rise, I then shaped into boules and proofed them for 30 minutes in the box. Pictures follow.

First, the items I purchased yesterday at Wal-Mart ...

Here it is all set up with the Honey Whole Wheat dough inside the box. Notice that the probe thermometer is sitting on top of the covered bowl.

The temperature at the top of the bowl. Note, when I finally got curious enough and stuck the probe directly into the dough, it registered about 92 deg F -- far higher than I thought it would be.

And, finally, the finished bread.

Things that surprised me:

* The box never ever felt warmer to the touch than the ambient surroundings. That could be because the ambient room temperature was 75 deg F. Perhaps in cooler weather, I would notice a difference.

* The internal temperature of the dough reached 92 deg F. I wouldn't have thought it would've been that warm. It took about 90 minutes for a first rise, 45 minutes for a second rise, and a 30 minute proof using this box. As long as I can count on that amount of time in colder weather, I'm satisfied with the results.

* While the tub that I bought will defintiely accomodate a half-sheet pan, I was also hoping it would accomodate two of my workbowls. Alas, it was about 6 inches two short. Perhaps I'll replace the tub with something slightly longer so that I can fit what I need under it.

[alanamoana]

tino, if you're concerned at all about the internal temperature of your dough, i would replace the metal sheet pan with a plastic one and invert it over the heating pad. that way, you get some air insulation and the direct contact between the metal sheet pan+heating pad+mixing bowl+dough won't happen. unless of course, this isn't a problem at all

looks like a pretty good setup...and cheap too!

[tino27]

I don't think I am concerned as much as surprised. I figured the dough might get to 83-86 deg F. I'm going to have to try a few other kinds of dough to really get the feel for the right setting on the heating pad.

The other thing I thought about doing is placing a cooling rack between the sheet pan and the bowl. That would elevate the bowl about 3/4 of an inch about the heated surface.

[cognitivefun]

seems that the dough is getting way too warm. I like to see it around 70F or so for better flavor development.

[alanamoana]

seems that the dough is getting way too warm. I like to see it around 70F or so for better flavor development.

←

is this just so that the proofing takes longer? often, that is the temperature of the dough off the mixer. with the yeasties going at it, i would think that the dough will get warmer during proofing?

[Bill44]

seems that the dough is getting way too warm. I like to see it around 70F or so for better flavor development.

←

is this just so that the proofing takes longer? often, that is the temperature of the dough off the mixer. with the yeasties going at it, i would think that the dough will get warmer during proofing?

←

A good point raised here, dough will generate some of it's own heat during proofing. The bigger the lump of dough the more heat in the core. This can be overcome to some extent by using cool or cold water in the dough mix.

[tino27]

Clearly the thing for me to do here is a comparison batch, no proofing box, and monitor the temperature of the dough at current room temperature. I always use room temperature water when I make my doughs -- the only time I've used cold water is when I was playing around with Reinhart's Pain a l'Ancienne from BBA.

Although I forgot to take a picture of it, the crumb and flavor of these loaves was the same as previous batches I have made without the use of a proofer -- so the higher heat didn't seem to affect them negatively all that much.

I would definitely like to see these temperature quite a bit lower, 75 - 80 deg. I'm not looking for fast results, just consistent ones.

I'll make a comparison batch, sans box, this weekend and post the results.

ETA: I've seen a number of books that cite that the dough should ideally be between 77-81 deg F when it comes off the mixer.

Edited September 7, 2006 by tino27 (log)

[cookman]

The only difference is that I bought a heating pad made for dogs (puppies actually) that is 100% waterproof.  (Actually I bought two, because at that time my basenji was in whelp and I needed one for the puppies too.)  I still have the one I use in the kitchen - it is also handy for gently heating cream and keeping it warm over a long period of time for making clotted cream.  There are a few other less common uses.

waterproof heating pad

the medium size

←

Interesting product, andiesenji. The website says it keeps a consistent temp of 98-101. A bit off-topic here, but that sounds like the ideal temperature for slow-melting chocolate and keeping it in temper. Any experience with this?

[andiesenji]

The action of the yeast in the dough does generate a lot of heat. 100 pounds of dough in a dough trough will be very warm when you sink an arm deep into it to punch it down or to grab an armful to place on the bench.

Edited September 7, 2006 by andiesenji (log)