Saturday, October 22, 2011

Notes on Baking Bread

Even once I had a handle on basic techniques like dough-shaping, I found that the bread I made at home wasn't as good as the bread I made at NAIT, where they have commerical equipment like proofing boxes and deck ovens.

Here are some quick notes on using household kitchen items to replicate the equipment in professional bakeries and bake better bread.


Proofing

I've always felt that my bread doesn't proof as well at home as it does at school.  At first I thought this was a temperature issue, so I tried fermenting and proofing my bread in increasingly warmer corners of the house.  Turns out humidity was the more important factor.

In commercial kitchens bread is proofed in proofing boxes.  These are fridge-sized compartments that are temperature- and humidity-controlled.  They stay between 20°C and 30°C, the temperature range at which yeast is most active, with a relative humidity of about 70%, which prevents a dry skin from forming on the dough.

I do my proofing in a cold oven, because it is an enclosed, draft-free space.  To mimmic the humidity of a proofing box, I tried scalding a small pot of water, putting it on the bottom rack of the oven, then proofing my dough in a lightly greased casserole on the top rack.  The pot of water releases vapour, and gently warms the air in the oven.  With the added humidity, the dough develops the ideal soft, tacky feel.  Success.


Baking

Whether you're searing a steak, sautéeing mushrooms, or baking a loaf of bread, you're trying to balance the desired doneness of the interior with the desired doneness of the exterior.  For steak, we want a heavily caramelized crust on the exterior, but pink, mid-rare flesh on the interior.  We apply very high heat to develop the crust before the interior is overcooked.  If we applied the same high heat to a large roast, the exterior would burn before the interior was cooked.  For roasts we cook at a lower temperature so that the delicious brown crust is finished at the same time as the pink meat inside.

With bread we also want a deeply caramelized crust.  Besides simply cooking the interior of the dough, we also want to maximize something called oven spring.

As the dough heats up in the oven, the little gas pockets that developed during bulk fermentation and proofing expand greatly.  The yeast also has one last hurrah, binging on sugars and expelling carbon dioxide, but this does not account for nearly as much rise as the simple thermal expansion of gases.  The dramatic rise in the first few minutes of baking is called oven spring.

To maximize oven spring we heat the dough rapidly and evenly in a moist atmosphere.  The quick heating ensures that the air pockets deep inside the dough have a chance to expand before the exterior bakes.  The steam prevents the exterior from forming a crust, which would hinder spring.

To rapidly heat the dough, professional bakers use deck ovens.  The dough is placed directly onto a uniform stone or ceramic platform, called the floor or deck.

To mimmic the deck at home, I use a heavy sheet pan, inverted so that dough can easily slide on and off.  You could also use a baking stone.

Commerical bread ovens also have steam generators.  Immediately after the bread is placed on the deck, the baker injects steam into the oven.

To create a similar effect at home I was told by a few people to put a metal tray on the bottom of the hot oven, and to throw a handful of ice onto it after the dough has been loaded.  Using ice, as opposed to water, will supposedly lengthen the release of steam into the oven.

I find I get better oven spring by throwing boiling water onto the hot pan.  You get much more steam much faster.  Believers in the ice method say that the steam from boiling water dissipates before the oven spring is complete.  For my most recent batch, I put about three cups of boiling water onto the hot pan, and there was still a bit left when I pulled the bread out thirty minutes later.

Use a very heavy pan as your steam generator.  Thin aluminum pans don't hold much heat, and therefore won't create a lot of steam immediately.

My first time I used a Pyrex casserole.  It cracked.  Now I use a heavy stainless steel braising pot.

3 comments:

  1. Fascinating!! I'm not sure how I would achieve the humidity proofing when I have a dozen buns rising but it will be interesting to try this sometime for bread as I always have trouble getting good results with bread. Maybe that is why I prefer making buns to making bread. I think back to the old days when Mom was baking bread. There was probably always a reservoir on the side of the stove with hot water in it and a pot of water on top of the wood stove. The windows in winter always had a coating of ice which would be an indicator of high humidity. I wonder if Mom found bread didn't work as well once she was using an electric stove and we had a forced air furnace.

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  2. Some Kitchen Aid ovens have steam-assist for bread proofing.

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