New Giveaway - Wort Monster Conical Fermenter!

Home Brew Forums > Home Brewing Beer > Brew Science > Calculate PPG of grain




Reply
 
LinkBack Thread Tools Display Modes
Old 04-02-2012, 04:19 PM   #1
Adeering
Feedback Score: 0 reviews
Recipes 
 
Join Date: Jan 2012
Location: Sherwood, Arkansas
Posts: 656
Liked 42 Times on 35 Posts
Likes Given: 4

Default Calculate PPG of grain

Im working on an android app to correspond with Beersmith. beersmith files dont export the estimated OG so i have to calculate it. I know the equation for that, the problem comes from calculating the PPG to use. Beersmith gives the moisture, diastatic power, protein, coarse fine difference and yield. Is there a way to calculate PPG for the grains with this info?



__________________
Primary: None
Secondary: None
Bottle Conditioning/Carbonating: Jasmine Green Tea Blonde
Kegged: Hop n Pop #54
Bottled: None
Next Brews: Dionysus' Ambrosia, an Amber Ale, Dragons Breath, and many more

Check out my Android Brew Day Assistant BrewAide
Adeering is online now
 
Reply With Quote Quick reply to this message
Old 04-02-2012, 04:35 PM   #2
944play
Feedback Score: 0 reviews
Recipes 
 
Join Date: Jul 2008
Location: Santa Rosa, CA
Posts: 2,738
Liked 34 Times on 31 Posts
Likes Given: 56

Default

I believe yield * 46 = ppppg.
http://www.howtobrew.com/section2/chapter12-3.html



__________________
OD: ?
Pri:-
Keg: Simple AIPA (2-row, Chinook, Cascade, WLP090)
944play is offline
 
Reply With Quote Quick reply to this message
Old 04-02-2012, 05:24 PM   #3
Adeering
Feedback Score: 0 reviews
Recipes 
 
Join Date: Jan 2012
Location: Sherwood, Arkansas
Posts: 656
Liked 42 Times on 35 Posts
Likes Given: 4

Default

That seems to check with what beersmith is showing as the potential. Thanks now i can do the last few calculations for the app.

__________________
Primary: None
Secondary: None
Bottle Conditioning/Carbonating: Jasmine Green Tea Blonde
Kegged: Hop n Pop #54
Bottled: None
Next Brews: Dionysus' Ambrosia, an Amber Ale, Dragons Breath, and many more

Check out my Android Brew Day Assistant BrewAide
Adeering is online now
 
Reply With Quote Quick reply to this message
Old 04-03-2012, 04:49 AM   #4
ajdelange
Senior Member
HBT_SUPPORTER.png
Feedback Score: 0 reviews
Recipes 
 
Join Date: Aug 2010
Location: McLean/Ogden, Virginia/Quebec
Posts: 5,206
Liked 452 Times on 371 Posts
Likes Given: 13

Default

Quote:
Originally Posted by Adeering View Post
Im working on an android app to correspond with Beersmith. beersmith files dont export the estimated OG so i have to calculate it. I know the equation for that, the problem comes from calculating the PPG to use. Beersmith gives the moisture, diastatic power, protein, coarse fine difference and yield. Is there a way to calculate PPG for the grains with this info?
Yes. You start with the coarse grind dry basis yield. This will be a number close to 80% for base malts and lower for higher kilned ones. 80% yield means one pound of grain (dry basis) will yield up 0.8 pounds of extract. Suppose you add 8 pounds of water to 1 pound of this grain. You will now have 8.8 pounds of solution containing 0.8 pounds of extract so it will be an 100*0.8/8.8 = 9.091°P solution. Now you need the specific gravity of a solution of strength 9.091 °P. I put details of how to calculate that, including a code fragment in #27 at http://www.homebrewtalk.com/f128/estimating-abv-using-brix-refractometer-317679/index3.html. The answer here is SG(9.091°P) = 1.03627. Thus your solution has 36.37 points. You now need to know the volume of it and to do that you multiply the specific gravity by the density of water to obtain the density of the solution at 20 °C. This is .998203(kg/L)*3.78541178(L/gal)*(1/0.45359237)(pounds/kg) *1.03627 = 1.03441 = 8.63255 pounds/gal. Your 8.8 pounds of solution thus has volume 8.8/8.63255 = 1.0194 gal. You have added 1 pound of grain to water to make up 1.0194 gal of solution which is 0.980969 pound per gallon and you got 36.37 points. Thus an 80% malt would be expected to yield 36.37/0.980969 = 37.0756 ppppg.

If you put 1 pound of pure sugar into 8 pounds of water you would have a 100*1/9 = 11.1111°P solution with specific gravity 1.04465. The density of this solution would be 0.998203 *1.04465*3.78541178/.45359237 = 8.70236 pounds/gal so the 9 pounds of solution would have volume
9/ 8.70236 = 1.0342 gal and the sugar (extract) addition would have been
1/1.0342 = 0.966931 pounds per gallon from which you got 44.65 points for
44.65/0.966931 = 46.177 ppppg

Note that 0.8 times this is 36.9416 which is very close to the 37.0756 we got by going through the detailed calculation for 80% HWE calculation. Thus many home brewers simply calculate ppppg by multiplying 46.177 (or some number close to it) by the percentage extract. The reason this is not exact is that the pppg depend on the strength of the solution though the variation is small. Another way of saying this is that density (or specific gravity) is not a linear function of strength (°P) though it is annoyingly close to being so.

It's late and I hope I got all those numbers right.
__________________

Last edited by ajdelange; 04-03-2012 at 12:14 PM. Reason: Fixed 11.111P
ajdelange is offline
 
Reply With Quote Quick reply to this message
Old 04-03-2012, 05:43 AM   #5
944play
Feedback Score: 0 reviews
Recipes 
 
Join Date: Jul 2008
Location: Santa Rosa, CA
Posts: 2,738
Liked 34 Times on 31 Posts
Likes Given: 56

Default

Quote:
Originally Posted by ajdelange View Post
100*1/9 = 1.1111°P

>snip<

It's late and I hope I got all those numbers right.
100*1/9 = 11.1.

Going to have to parse your post again to see how it is that volume grows with solute adds!
__________________
OD: ?
Pri:-
Keg: Simple AIPA (2-row, Chinook, Cascade, WLP090)
944play is offline
 
Reply With Quote Quick reply to this message
Old 04-03-2012, 12:18 PM   #6
ajdelange
Senior Member
HBT_SUPPORTER.png
Feedback Score: 0 reviews
Recipes 
 
Join Date: Aug 2010
Location: McLean/Ogden, Virginia/Quebec
Posts: 5,206
Liked 452 Times on 371 Posts
Likes Given: 13

Default

Quote:
Originally Posted by 944play View Post
100*1/9 = 11.1.
Fixed it!
Quote:
Originally Posted by 944play View Post
Going to have to parse your post again to see how it is that volume grows with solute adds!
Obviously your life will be much easier if you plug the math into a spreadsheet. The only tricky bit is inverting the Plato formula. You can use an inverse polynomial (there's one in the referenced post) or you can use Excel's Solver to do it or you can put in the closed form solution of the cubic equation.


__________________
ajdelange is offline
 
Reply With Quote Quick reply to this message
Reply


Quick Reply
Message:
Options
Thread Tools
Display Modes


Similar Threads
Thread Thread Starter Forum Replies Last Post
How to calculate Sodium from water analyzis spura Brew Science 6 03-15-2012 06:32 PM
Anyone know how to calculate this? Lodovico Brew Science 6 03-04-2012 04:20 AM
How do I calculate amount of Gypsum needed in my boil... preboil volume? wookiemofo Brew Science 3 08-13-2011 09:01 PM
calculate OG from Final eager_brewer Brew Science 4 04-06-2010 07:15 PM