The Fresh Loaf

News & Information for Amateur Bakers and Artisan Bread Enthusiasts

When is a biga ready?

lello's picture
lello

When is a biga ready?

Hi evrybody,


this is my first message to the community so please be polite :).


Here is my problem. I was baking Hamelman's pizza and after 12 hours of fermentation my biga looked like this


Biga after 12 hours


 


I think it was over fermented. I can't control the temperature, it was 25 °C (75 F). I could lower the amount of yeast (which was 0.2 %)  but I don't know how much should I lower it.


Any help is appreciated.


Lello


 

mrfrost's picture
mrfrost

Hamelman Bread formulas:


http://media.wiley.com/product_data/excerpt/72/04711685/0471168572.pdf


"...Knowing the signs of ripeness is very important: When the
poolish is ripe, the surface will be covered with small bubbles
-in
fact, you should see bubbles breaking through to the surface, indicating
the continuing activity of the yeast. If there is evidence that
the poolish has risen and then collapsed (you may see a "highwater"
mark on the sides of the bowl), then the poolish is past its
prime. A stiff-textured biga and a pâte fermentée are ripe when they
have domed and are just beginning to recede in the center
. The
goal is to have the pre-ferment at its full ripeness when you are
ready to use it, and therefore the correct yeast quantities will
increase and decrease as the seasons come and go. The amount of
yeast necessary for a poolish to ripen in 16 hours at 80°F might be
.08 percent of the poolish flour weight, but the same poolish might
need .25 percent yeast at 65°F. The other factor determining yeast
quantity is the duration of the ripening phase, with longer ripenings
needing less yeast. Below is a general guideline, based on a
room temperature of 70° to 75°F: The percentage of yeast is based
on the weight of the flour used in the pre-ferment, not the flour in
the overall formula. The percentages given are for fresh yeast.


LENGTH OF RIPENING % YEAST
Up to 8 hours .7 to 1%
Up to 12 hours .3 to .6%
Up to 16 hours .1 to .25%..."


ps: For instant yeast, use 1/3 of the quantity listed. For active dry, use 1/2 the amount.

lello's picture
lello

H, and thanks for the answer. I read what Hamelman writes but my problem is that following these percentages my biga seems to be overripen. If I let it stay for 16 ours, with 0.2 % of yeast than it has a very strong and intense smell like alcohol and acid, and from the description the surface is more like a poolish than a biga with a "domed surface".

mrfrost's picture
mrfrost

If not ready to use the biga when it is ripe, then try:

a. Cutting the yeast amount in half to extend, and/or:

b. Using cooler water, or:

c. Refrigerate when ripe. Let temper to room temperature when ready to use.

Otherwise, if possible, just try planning to use the biga when it appears ripe, (before it overripens), regardless of the time period. It's really not that complicated.

Good luck.