The Fresh Loaf

News & Information for Amateur Bakers and Artisan Bread Enthusiasts

Proofing Box

Wayne's picture

Proofing Box

Finally got around to building my "high dollar" proofing box.  First picture is the inside of the box w/transformer to the side.  Happened to have the transformer on hand from my day's as a research chemist.  Second picture is the outside of the box showing the temperature probe and the transformer.


Drifty Baker's picture
Drifty Baker


What is the wattage of the light bulb?  Now wouldn't it be nice if you could use an iron to inject some steam?


Way to go.  Let us know how it is working out.


Drifty Baker 


Wayne's picture

Hi Drifty:


I am using a 25 watt light bulb.  Dimensions of the styrofoam cooler are 12 x 12 x 17 inches inside.  Just a $1.88 cooler from WalMart.  The bulb holder cost $180.  A dimmer switch from Home Depot, etc. would probably run you around $6 or so.  Have briefly tested this proofer and it eaisly maintains a temp. of 80 degrees, 75 degrees, etc. just by adjusting the transformer of dimmer switch.


Wayne's picture

The bulb holder really did not cost $180, it was actually $1.80

npsmama's picture

I know this is an old thread but just wanted to say thanks as I had never thought of the dimmer switch idea.

Today for the first time (reluctantly and only because my dough wasn't rising) I put a 60watt lightbulb in a cardboard box and used my cheesemaking thermometer to improvise as a proofing box.

It worked very well but I did have to play around with opening the lid to get as near to 77F as I could as it got too hot.

A dimmer switch would be ideal. 

Kate's picture

Really nice, Wayne! I built one of these using the bulb holder from an old lamp and put it inside a small stool with a tin foil hood - not nearly as clean looking as yours, but worked in a pinch with what I had on hand. I like the dimmer switch idea, too. 

pumpkinpapa's picture

I found plans for a water bath proofing box at the Bread-bakers site

I have a few of those bins around some where's, I'm going to dry to put it together over the next while when I have free time. 

Wayne's picture

Interesting concept pumkinpapa................might be interesting to build and compare the two boxes. 

andrew_l's picture

You can buy something suitable ready made and quite inexpensive....
A thermometer probe can be dropped down the little vents - which can be opened / shut to control heat. I've only used mine for proofing once as my kitchen tends to be quite warm, but it worked a treat. And then worked fine for germinating cherry tomatoes!!

mountaindog's picture

Wayne - That looks great...yet somehow the transformer device reminds me of something Wile E. Coyote would send away for and end up blowing himself up with  ;-) Just kidding...


I need to do this too but have been stalling since my wood stove has been providing good proofing environments, but I know I will need something like this in the spring when the stove will not be going so much, yet the house will still be cool.  

Andrew - I like your seed starter kit idea, esp. with the clear dome and the trapped humidity. I already have 2 seedling heat mats from years of starting my own seeds that I plan to use in my homemade proofing box when I get around to it, but I need to use a much bigger box as I do a lot of big loaves at the same time.

Wayne's picture

Thanks Mountaindog.......You may be right, I sometime remind myself of Wile Coyote (my favorite cartoon character when I was a younster).  For a much biger box, you could just get a bigger styrofoam cooler and maybe a 40 watt bulb instea of a 25 watt.  By the way, my transformer did no come from "Acme".  Ha

Loafer's picture

That doesn't scare you?  At what point does the "cooler" melt down and become a flaming plastic fired oven for your dough?

 Good for you for working with the materials at hand, but I think that the aquarium heater option seems a bit uh... safer?


Wayne's picture

This set up is entirely safe.................the auto ignition temperature of styrofoam is in the range of 750 degrees F.  The 25 watt bulb, operated at 40% of its wattage will never generate sufficient BTU's to reach this temperature.  So, thanks for your concern, although misplaced. By the way, don't get electrocuted by a possible shorted aquarium heater. Duh................