# Bread proofing times fridge versus room temp

I've recently started to try to make my own bread. I am starting with baguettes because they seem like a fairly straightforward kind to start with. Recipes I've seen online will either say to leave the dough at room temperature to proof, or in the fridge to proof for a longer period of time. It makes sense to me that because the temperature is lower, the yeast takes longer to do its thing. However since I work during the day, I can't really follow a recipe that has the dough proff for something like 6 hours and have it finish at a reasonable time.

My question is, is there a way to convert a recipe from proofing time on the counter to proofing time in the fridge or vice versa? I.E. if it takes 12 hours on the counter, will it take 24 hours in the fridge? Does the amount of yeast added factor into it?

Basic room temperature breads don't prove in 6 or 12 hours, 30 minutes to 2 hours is more typical. The overall process from start to finish including baking may be 6 hours. Sourdough breads and enriched doughs like brioche and challah can take much longer to prove at room temperature.

As for calculations no, there's no straightforward time conversion between room temperature and refrigerator proving because there are too many factors like actual room temperature and yeast potency which vary how long the bread will take to prove in other location. In home baking you prove to result, not to time, i.e. you prove until bread has doubled or tripled in size however long it takes.

Refrigerator proving really does slow it down by a very large degree, I don't have a figure for it but what I will say is that if you made a dough in the morning then put it in the fridge for 10 hours it still may not be fully risen. This isn't a bad thing, it means you have a lot of flexibility. I often make pizza base the night before then leave it in the fridge for an entire day before using it with excellent results (that won't work for all types of bread as it may be too much proving).

What that means for you is that you can be strategic with it; make the dough in the morning and then put it in the fridge to prove, when you come home if it isn't fully risen it's not a problem as you just take it out of the fridge and let it warm up on the counter until it has. Or you can make the dough in an evening, rise it overnight and bake it in the morning.

As GdG pointed out, yeast becomes much less effective at fridge temperatures. A long time ago I was taught a (very rough) rule of thumb:

For every increase in temperature of 10°C, the speed of chemical reactions doubles and biological reactions speed up by a factor ten.

That is of course only valid within a fairly narrow range, and should be taken with a whole lot of salt. For all practical purposes, though, the yeast activity effectively goes into slow-motion when the dough is at fridge temperature. It's still active until the dough has cooled down completely, but after about 30 minutes very little actual leavening occurs. (According to the rule-of-thumb above it ought to slow down by a factor of 100 or so.) The yeast still lives on (and creates nice flavours), but the difference in volume after one hour and after ten hours is fairly small.

As an aside, I'd suggest that you start by something easier than baguettes if you're a novice baker. Baguettes are a lot more complicated than you'd think, judging by the very short list of ingredients (Only flour, water and salt. Yeast optional(!) ). The dough is very wet and awkward to shape. (And if you reduce the hydration you miss the loose crumb of a proper baguette.)