Q: I am making the famous no-knead bread from the NYTimes /Jim Leahy adaptation published a few years ago. I'm doing a variation with multi-grains, and I can see it is rising very very slowly. I had questioned the yeast, in the past it was ok, from another unrisen loaf. But the dough seams warm - I do think SOMETHING is happening, just not fast. I put it together at 10pm last night, so it's been 13 hrs now. How long can I leave it to continue to rise? the recipe calls for 18-20 hrs. If I leave it overnight a second night - totaling more like 36 hrs - will it become rotten or rancid or otherwise toxic? If not I'm happy to let it go and see what happens. Could a person add yeast at any point, or would that be too hard to mix in? Does yeast need to be thoroughly mixed to work correctly, since it's actually a chemical process?
A: I think a few things about this, but I want to preface all my thoughts with the fact that while I have baked bread, I am not a bread baker (like Jim Leahy, whose bread is incredible). It's a very specific arena.
That said, I'll tell you what I know.
1. whole grains are much heavier, so: a) it takes more force/energy to make them rise, and they may never rise as much and b) yeasts, which are tiny organisms, process all grains differently(and some not at all). so that could slow the process, and/or just limit it.
2. sometimes part of the yeast in a packet/block will die and recipes will depend on all the said yeast in a recipe being active. However, because yeast is essentially a bacteria, it actually reproduces while eating the protein in the flour, and releasing the gas that in-turn makes your bread rise. So, if there is any active yeast at all in what you added, the population will eventually get there. It just may take time. Of course this is one of the real skills of a bread baker, knowing when bread has risen the correct amount (or when the yeast is at the correct population).
This also means that you don't have to add yeast late in the process, but if it did come to that I would advise just starting over.
3. The extra time this may take exposes you to some variables. There are good yeasts ad bad yeasts. molds are also bad. If you see any weird colors, or smell any really funky sour, acrid or rancid smells, toss it. Strong yeast aromas, and slightly sour smells are ok. In short, it should smell good, and don't doubt your judgment, if it's bad you will know, if you have a bad feeling about it trust your instinct.
4. Having said all that. There is a serious science and skill to bread baking. Where the recipe is a specific equation that equals a delicious loaf of bread. When you futz with components of that equation, the result will be different, for better or for worse.
I'd say give you bread a little more time, and then, even if it hasn't risen as much as you'd like, bake it anyways.
(as long as it hasn't gone bad) I'd love to hear how it turns out.