I often don't get much volume increase in sourdough preferments (calling it a sponge or sourdough doesn't increase the volume). Nor do I get any volume increase at all in the opara (the scald-sponge from combining the preferment with scalded rye malt for dark Baltic ryes).
My bulk ferments usually have decent volume, and when I make a double batch I have to have a container big enough to hold the expanded dough and not have the collected CO2 blow off the lid.
I looked for advice and found that I wasn't supposed to have a tight lid on either the preferments (including the opara) or on bulk fermenting dough (but it looked that way on TV!), even in the fridge.
Throwing a towel over the top of the container isn't ideal either as it tends to absorb moisture that should go into the flour.
So the recommendation is to put a lid on the top of the container but not to snap it on tight, e.g., put a plastic lid on upside down.
So what do people with experience who get the doubling of the preferments and the dough think? Loose cover to let the excess CO2 escape but keep the moisture in? Maybe a towel over the upside-down lid just to keep it in place?
Thanks
I used to use a sheet of plastic wrap. That worked fine. Now that I have a straight-sided tub, I usually use its lid. It seems to work all right even snapped on, but it would be easy to leave a corner loose. I always oil the tub first and turn the dough over after putting it in, to leave a film of oil on the top so it doesn't dry out. The oiled surface (spray oil, actually) helps me slide the dough out without tearing or deforming it.
You could try a shower cap; they're not completely airtight.
Good suggestion. I'll have to ask my wife if she can spare a couple.
...plastic shower cap. And they fit different sized bowls.
If you want to use a dish towel--dampen it.
I just used a shower cap for a Pullman loaf. The dough rose above the top of the pan so I had to bake it uncovered. I had pulled to cap up and the dough didn't touch it.
I use regular gallon storage bags that I cut along the sides to open them into sheets. An elastic band to keep them in place. Or you can stick the bowl into a grocery bag and tuck it underneath the bowl to limit air circulation.
Good idea for the plastic bags.
Thanks
I just lay the plastic wrap sheet on top without securing it. It almost always works fine without.
That would be convenient. I'm currently using the container lids upside down for a loose cover, with a towel above secured with rubber bands. That also holds the upside-down lids on.