Author Topic: Math check  (Read 948 times)

Offline ryang

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Math check
« on: October 22, 2010, 11:34:31 AM »
I need to add 17 extract points to primary fermentation.  I currently have 6 gallons liquid at 1.063

by my math, I need to boil 2.7lbs dme (45ppg) in one quart water.  correct?

(378+X) / 6.25 = 80
X=142

142 / 45 = 2.71 lbs dme

Offline tschmidlin

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Re: Math check
« Reply #1 on: October 22, 2010, 11:53:21 AM »
No, x=122.

It's still 2.71 though, if you're using 45 points per pound.  You might have trouble dissolving that much DME in a quart of water and might have to go to 2 qts.  That would take 3.16 lbs of DME.
Tom Schmidlin

Offline ryang

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Re: Math check
« Reply #2 on: October 22, 2010, 01:10:13 PM »
oops, yeah I had 122 written on paper.

I was wondering too if that much extract would go into just one quart... I guess I will find out.

Offline tschmidlin

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Re: Math check
« Reply #3 on: October 22, 2010, 08:16:26 PM »
In retrospect, it might be ok.  That's about a 56% solution, which if it was straight sucrose would definitely work.  So I think 2.2 lbs will dissolve fine in 1 qt.  But let us know when you try it.
Tom Schmidlin

Offline ryang

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Re: Math check
« Reply #4 on: October 22, 2010, 10:20:41 PM »
well I did it.  it worked, but it was quite syrupy.  trying to think of a good way to describe the consistency...

warm maple syrup consistency I think closely depicts this.

Offline icedbreeze

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Re: Math check
« Reply #5 on: November 06, 2010, 02:26:49 PM »
I need to add 17 extract points to primary fermentation.  I currently have 6 gallons liquid at 1.063

by my math, I need to boil 2.7lbs dme (45ppg) in one quart water.  correct?

(378+X) / 6.25 = 80
X=142

142 / 45 = 2.71 lbs dme

This is kind of interesting to me.  Can anyone point me to a link or information on "extract points"?  Or if its easy simple enough for a post explain it there? :D

Offline BrewArk

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Re: Math check
« Reply #6 on: November 06, 2010, 02:36:55 PM »
<snip>

This is kind of interesting to me.  Can anyone point me to a link or information on "extract points"?  Or if its easy simple enough for a post explain it there? :D

Try this:
http://www.brewingtechniques.com/library/backissues/issue1.3/manning.html
Beer...Now there's a temporary solution!

Na Zdraví

Offline gordonstrong

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Re: Math check
« Reply #7 on: November 07, 2010, 12:04:07 AM »
It's simple enough to explain here.

"Extract points" in this context means dropping the "1." from the gravities and just dealing with the decimal portion as if it were the whole number.  I usually call them gravity points, but they mean the same thing.

"I need to add 17 extract points to my 1.063 beer" means he wants to raise his 1.063 wort to 1.080 (80 - 63 = 17).

You measure the total points in your fermenter, so you multiple those extract points (63) by the volume of wort (6).  That's the 378.

The equation is set up properly.  Adding 1 quart of water raises the volume to 6.25 gallons.  So he's trying to find how many total points does he need to add to his existing 378 to give a gravity of 1.080 in 6.25 gallons of beer.  Solving for X gives 122.

You can add those points different ways.  Dry malt extract has 45 gravity points per pound.  So divide 45 into 122 to get the number of pounds of DME to use (2.71).  Liquid malt extract is around 36 points per pound.

Note that this assumes the DME takes up no volume, but I'm assuming the liquid will be boiled so the final volume of the portion added is about 1 quart.
Gordon Strong • Beavercreek, Ohio • AHA Member since 1997 • Twitter: GordonStrong

Offline icedbreeze

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Re: Math check
« Reply #8 on: November 07, 2010, 07:31:04 AM »
ah ha ok.  Thanks for clearing that up for me.  I'm trying to learn everything I can without over-doing it and confusing myself lol.  I have a whole word document of information from these forums I might find useful later on. :P

Offline oscarvan

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Re: Math check
« Reply #9 on: December 02, 2010, 10:22:52 PM »
I'm trying to learn everything I can without over-doing it and confusing myself lol.

You and me both. Although I think "overdoing it" is relative...are you asking me, or my wife?...;D
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