The Final Proof

Tuesday, May 25, 2010

Hmm…this sounds like something my mathematician husband should be working on. But turns out it has some relevancy to bread baking too.

Last week I spent a whole lot of time discussing shaping and why it’s your last chance to get things right with your bread. Its all about walking the line between tightness and slackness in the dough, and getting it just right so you get a good final rise in the oven.

So the next steps involve the final proof and the bake.

The Final Proof serves 3 important functions: first, it gives more time for flavor to develop in the dough; second, it lets the dough relax after the stressful shaping stage; and third, it allows the dough to rise again.

Flavor: The final proof is a resting period for the bread, which allows the yeast to keep breaking down the starch into sugar and release flavor. This is the same concept as the bulk fermentation stage, in which the yeast are kept busy chomping on starch and producing acids for flavor and CO2 as a by-product.

Relaxing: The shaping stage is also quite stressful for the bread. You’re pushing, prodding, folding and manipulating the dough; after that kind of work out, you’d need an hour or so to relax too.

Rising: The shaping stage also degasses the dough, so you need to give it a chance to re-puff up. The final proof gives the yeast more time to produce CO2, which is then trapped by the gluten strands, and produces air pockets in your final bread.

So the final proof is important, but like most aspects of the bread baking process is fraught with the potential for tragic missteps (a bit of hyperbole, but after going through all the time and effort of the preceding steps, to blow it on the final proof is pretty devastating).

What helps me in understanding this process is that I’m working with a living creature. And as a living creature, it is not completely manageable or able to be manipulated. It has a life path of its own, a metabolism of its own, a mind of its own. And we’re just trying to catch a ride on its life cycle to get to the place we want to get to. So, we put it in mildly predictable environments and hope it does what we think it will do. But it’s a living creature, so we have to appreciate and be respectful of the idiosyncrasies and lack of predictability inherent in that.

Now what that means for the final proof is this: the yeast has been eating for a long time now. Hours, sometimes even overnight. At some point the yeast eats all the food available; its broken down all the starch, eaten all the goodies you gave it to chomp on in exchange for flavor and CO2. And so, it gives up. I’m not sure if it actually dies, but it stops doing what it was doing when there was food around – it stops eating and metabolizing.

This is very bad for the bread. When the yeast stops, it no longer produces CO2, which means the dough deflates. You can tell if you’re bread has gone too far, it starts to look dead. Its listless and sort of wimpy looking. You want perky bread, that bounces back slightly when you push on it. It’s a sad day when your bread overproofs.

What is the result of overproofed bread once it bakes? Sad, sad bread. This gets a little into the baking section, but here’s what happens when the bread heats up in the oven. It goes through a temperature range that is optimal for yeast metabolism. And the yeast just start producing CO2 like crazy, just pumping it out, and this is what makes your bread rise in the oven so much. It’s the last hurrah for the yeast (before they hit 160 degrees and die). So, if you’re yeast have already given all the CO2 they can during the final proof, there’s nothing for them to do in the oven. Which means, your bread is not going to rise. Hence, sad, sad bread.

Ok, but on the flip side, if you catch your dough at just the right stage during the final proof and then slip it into the oven, you get a great rise on your bread. Air pockets expand in your dough and it puffs up to just the shape you want. But…the baking discussion will have to wait for another day.

Until next week, enjoy these pictures of this week’s breads.