September 21, 2012 - 8:40am
Overnight retarding
When making sourdough, and after divided and placed into bannetons, I retard the dough overnight in the refrigerator at 47 degrees. How long can I safely do this before baking? 12 hours, 15 hours, 24 hours? I like the bread to have a pronounced sour flavor but I don't want to run the risk of overproofing the dough.
Share
For at least the first loaf, you'll want to occasionally check on the rate it's proofing; worst case scenario, you over-proof and 'lose' a loaf. I've retarded for several days, and not overproofed, but my starter practically stops at 6C.
at such high temperatures since my fridge runs at 38 F, but I will say it depends on the dough. Have done low hydration dough like bagels for 48 hours and 24 hours is standard. Spelt breads can be over proofed in 4-6 hours. So I'm guessing it depends on the grains, hydration amount of fermentation before hitting the cold, etc. The multi-grain SD with kamut, spelt rye and WW was nearly fully proofed at 7 hours this morning when I checked it and it was placed in a basket right after S&F's and straight into the fridge with no ferment on the counter.
The lower the temperature, the longer you can retard (up to a point) and the more sour the bread will get.
This is because the growth rate of the LAB relative to the yeast goes up as the temperature goes down. You pick the temperature to determine how long it will take the yeast to proof the dough and you get the acidity that the LAB produces in that time. It will work down to about 2°C but there are other processes that are going on in parallel that you have to worry about as the time goes up (like gluten breakdown). Try three loaves and bake them sequentially at 12, 18, and 24 hrs. See what works, then modify the experiment to focus on a more narrow time span.
I just read and article by Peter Reinhart on the very subject, you may find it interesting as well.
http://www.fornobravo.com/pizzaquest/peters-blog/44-peters-blog/416-peters-blog-sept-15th-cold-fermentation.html
Gerhard
I found Peter Reinhart's post interesting as well, though I think he places too much emphasis on the enzyme activity without accounting for the system-level effects of the other processes that are going on in parallel. For the backup data check out:
Saunders, R. M., H. Ng, and L. Kline. 1972. The sugars of flour and their involvement in the San Francisco sour dough French bread process. CerealChem. 49:86–91.
There are two distinct events going on in your question. One questions the possible length of cold fermentation at a given temperature and the other is the not mentioned question regarding your sourdough, your recipe and all of your techniques. Peter Reinhart has written a lot of good information on the subject in the link mentioned previously and in some of his books.
A third question comes to my mind; Why is your refrigerator at 47° ? This is too warm for just about anything other than fermenting various beverages....and maybe that is why it is at 47° ! Follow the advice given above and read all that you can about cold fermentation. There is not a simple answer to your question without knowing your sourdough and everything that transpires up to the point of retarding the shaped loaves.
Jeff