Major Holes in Yeast Bread

[lizztwozee]

Greetings, bakers. I've recently leased a commercial kitchen space to bake a poolish-starter white/whole wheat flax bread to sell at Farmer's Markets. The oven I'm using is a gas convection, with no provisions for steam or stone baking. Just racks and the fan. At home, I was baking on a stone, with steam provided using an old sheet pan and chunks of marble in the bottom, heated with the preheat, and hot water splashed on, when the loaves went in. Now I load the loaves onto a sheet pan, and shove 'em in at 400°F for about 15-20 mins., depending on the size. I get a nice oven burst, and they look great, but I'm finding more tunnels at the tops, than I did with the home baked loaves.

Here's my recipe:

Poolish: 100% hydration

12 oz. strong flour

12 oz. water

1.5 tsp. instant yeast

ferment for at least 4 hours.

add:

65 oz. water (62% hydration)

90 oz. strong flour

20 oz. whole wheat flour

2 oz. ground flax seed meal

1 oz. whole flax seeds

3 T. salt

1.5 tsp. instant yeast

The first rise is at 100° in a warming oven, the second after shaping is at room temperature, which is about 65 degrees (I work in a meat processing plant), and each takes about 1.5 hrs.

I form the loaves in the standard baguette manner, fold, seal, fold, compress and roll a bit, to make 17 oz. torpedo shaped loaves.

What is your experience with large holes at the tops of breads? Are they formed during shaping (my internet search indicated "poor machining of dough" as a reason -- I have no idea what that means!), or is it because of the baking temperature/time/method? Help! No one will buy my loaves if they're holey! Thanks in advance for your expert advice.

[lizztwozee]

Oh, and the oven has a large sign that says something like "fan must be on if gas is on" -- does this mean I must bake with convection? I didn't use it at home, but baked at 450°, rather than 400° with convection.

[Deus Mortus]

Well poor machining of dough means the yeast isn't spread evenly and that would make larger bubbles form in some area's of the bread. Doesn't seem like that is your problem though, maybe the lack of steam is making the bread dryer and thus less stable while baking?

[jackal10]

Sounds like you are suffering from a "flying crust". The top crust drys and stays inflated, but the crumb collapses underneath it

a) Reduce the final proof time, maybe by half. You want most rise as oven spring.

b) Make sure the cust doesh't dry out during proof, for example by proving in a plastic bag, or covered racks

c) Turn the loaves over before baking so the dryer crust is underneath

[dougal]

I know this as a "flying top".

While I wouldn't disagree with Jackal10's suggestions b & c, I think he may have (a) the wrong way round.

My understanding was that flying top is usually caused by under-proofing.

UK Flour Advisory Board link - http://www.fabflour.co.uk/content/1/49/bread.html

The fact that you are getting a really good oven spring ("burst") - even without stone and steam - also suggests to me under rather than over-proofing.

[jackal10]

Dougal is right

http://www.danlepard.com/forum/viewtopic.php?f=3&t=6&p=28

[lizztwozee]

Thank you, thank you! Yes, the underproofing theory makes perfect sense. I feel better about life now!