Proving Oven – part 1

Aight, this is an Instructional that’s meant to result in our Schleps being able to prove the dough she’s been labouring under for over a month now. The problem is a simple one, for the final proving of the dough it needs to have an environment of 24-27 degrees Centigrade with a humidity level of 80%. And it needs to be efficient, no turning the oven on and leaving the door open…

Currently we have winter out the window, so indoors is far from within the ideal bread proving range therefore we, or I, need to make a thing that can be the correct temperature and humidity and can contain several kilos of dough. That thing is some sort of container. Hmmmm.

Now bear in mind that this is a work in progress, but the first idea is to use an incandescent light bulb to heat up a mid sized container, say 15 litres, like a bucket. As heating elements go, light bulbs aren’t the best but they do basically what any other electrical oven does so why not implement it here.

So here’s me bucket:

At the top you can see a basic light bulb ceiling mount socket and a shortened power cable coming out. Its shortened cos we will eventually be plugging it into some science but more on that later. I put in a 40 watt bulb for a test to see how long it would take to get the “oven” temperature to the median of 27 C.
So plug it in and turn it on:

If you want some details they are as follows: ambient temperature was 20 C. Minimum temp required is 24 C, median is 27 C and maximum is 30 C. Turning the light on saw a rise in temperature to the min in ten minutes, the median in a further ten minutes and the max in a further 20 mins, giving a delta-t of about +1.5 C every 5 minutes.

In other words, a 40 watt light bulb in a mid-sized container can heat it up to bread proving temperature in about 20 minutes.

Turning the light off saw the temperature drop from the max to the median in four minutes, then from there to the minimum in a further ten minutes, with a delta-t of -0.5 C every two minutes. In other words this “oven” loses heat twice as fast as it gets it from the light source.

As the bread needs to be at the median temperature for several hours and you can’t keep the light bulb on as it would over heat the bread and who wants to sit in front of dough flicking a light switch on and off, it now requires the construction of a short-form thermostat control circuit. Of course it does. This will automagically switch the light on if the “oven” is cold and then turn it off when the “oven” gets too warm. So we will be building that next. But first, one thing noticed was the plastic smell which needs to be blocked from affecting the dough. For this we will try some aluminium foil wrapped round the interior of the “oven” which will also help keep it insulated. And also maybe get a better thermometer.
So stay tuned for the next exciting installment of “How Matthieu Gets to Make Stuff to Help His Lady”.

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2 Responses to “Proving Oven – part 1”


  1. 1 smoo June 6, 2010 at 8:21 pm

    I’m very impressed Matthieu with your ingenuity and dedication and wish you great success in your endeavours. I can only imagine the stress of living with a temperamental starter and the urgent necessity to do something ‘constructive’ about it.

    For some unknown reason it reminds me a very special elder sister and her pa making a most attractive, mauve-painted wooden house (box to the uninitiated) to accommodate her dear younger sister’s Winnie the Pooh and related soft toys (of which there were many). If only one could get the windows just the right size to maintain a constant temperature without creating a draft….. Of course that would be wasteful of electicity so give up on that idea. Or perhaps you too could sew little curtains for the windows. I suspect the starter really does need a special environment. Although one would not want to use lead paint in one’s starter house (or plastic fumes, or whatever it is they put in treated pine that kills you….) I shall await your version 2 with much hope and interest.


  1. 1 roast squash, tahini, pinenut salad « Fasting at the banquet Trackback on June 6, 2010 at 12:44 pm

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