Fermentation question - Home Brew Forums

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08-31-2012, 09:09 PM   #1
skinnyterror
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Aug 2012
Oceanside, Ca
Posts: 20

Hypothetical question here...

I've calculated my grain bill using a 68% efficiency and a gravity reading of 60gu's. Let say that my efficiency ends up being 75% and my new gu reading is around 67. So in order to get down to 60 gu's I need to add about 1/2 gallon of water. I plan on using a wyeast packet to ferment my beer and the packet states that there is enough yeast for a 5 gallon batch. Will this be enough yeast if I end up with more beer due to a higher efficiency?

08-31-2012, 10:30 PM   #2
RCCOLA

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Nov 2008
Northwest Arkansas
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You should make a starter for all liquid yeasts with 5 gal batches. Pitching a pack without without one will give a cell count which is less than ideal.

Here's a good free yeast starter calculator to play with. http://www.mrmalty.com/calc/calc.html

09-01-2012, 01:24 AM   #3
duboman
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Jul 2011
Glenview, IL
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Quote:
 Originally Posted by skinnyterror Hypothetical question here... I've calculated my grain bill using a 68% efficiency and a gravity reading of 60gu's. Let say that my efficiency ends up being 75% and my new gu reading is around 67. So in order to get down to 60 gu's I need to add about 1/2 gallon of water. I plan on using a wyeast packet to ferment my beer and the packet states that there is enough yeast for a 5 gallon batch. Will this be enough yeast if I end up with more beer due to a higher efficiency?
Yes your calculation is correct to add top off if your OG is higher than you want.

Yes you still should make a starter: Www.yeastcalc.com is another site, also allows for steps.
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09-01-2012, 01:36 AM   #4
agcorry00
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Aug 2012
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You can also use dry yeast if you don't feel like making a starter, but you don't have nearly as many options as you do with liquid.
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09-01-2012, 06:54 AM   #5
helibrewer

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Nov 2011
Santa Rosa, CA
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Quote:
 Originally Posted by skinnyterror Hypothetical question here... I've calculated my grain bill using a 68% efficiency and a gravity reading of 60gu's. Let say that my efficiency ends up being 75% and my new gu reading is around 67. So in order to get down to 60 gu's I need to add about 1/2 gallon of water. I plan on using a wyeast packet to ferment my beer and the packet states that there is enough yeast for a 5 gallon batch. Will this be enough yeast if I end up with more beer due to a higher efficiency?
Why not just make a bigger beer with 5 gallons? The convention is to call the gravity reading Original Gravity (OG).

Gravity Units could be mistaken for the gravity points per pound per gallon (PPG). For instance, DME yields 45 PPG so you should get 45 gravity points for every pound of DME per gallon. 10 pounds of DME would be 450 points divided by 5 gallons = 1.090 OG

If you add up all your gravity points and have a desired OG, you can solve for post boil volume.
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09-02-2012, 12:44 AM   #6
skinnyterror
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Aug 2012
Oceanside, Ca
Posts: 20

Thanks for the replies.

I do another terribly newbie-ish question... I looked at the calculators and understand the process of making the starter, but how long should I let the starter ferment before I add it to my wort? For example, if I'm brewing on a saturday, should I make my starter on a wed, thurs, fri? Also, once the starter is made do I pour in all the liquid into the wort that I have made, or do I want to drain liquid off of the top and just pour the trub in?

09-02-2012, 01:05 AM   #7
kscarrington

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Jan 2012
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A day or two ought to be fine. I usually go about a day and a half. The wort won't really do anything for your fermentation. You can cold crash to let everything settle then pour off most of the liquid, leaving enough left to loosen up the compacted yeast. I then let it sit and come up to room temperature by the time it's ready to pitch.