| Author |
Message |
    
Milan Bartolec
Junior Member
Username: Littlebro
Post Number: 83
Registered: 03-2003
| | Posted on Tuesday, December 21, 2004 - 06:02 pm: | 
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For the last couple of years, I’ve been using both ProMash and Ray Daniels Book “Designing Great Beers”. Love them both. A-lot. But this last week I came across a discrepancy while calculating the percentages of my malts in my grist bill.
I’m making a German Lager, Helles, and I want to follow the style guidelines which show 82.5% Pilsner malt, and 17.5 carapils malt. My Target OG is 1.050, and I make 10 gallons of finished beer.
Since I haven’t found a way in ProMash to enter the % of the grist bill (its calculated for you), I went back to the manual way of calculating the % with Ray Daniels formulas.
1. Total Gravity Points of Batch
10gallons x 50 (OG) = 500 Gravity Points for the batch.
2. Proportional amounts
82.5% of 500 = 412.5 Gravity Points from Pilsner Malt
17.5% of 500 = 87.5 Gravity Points from CaraPils Malt.
Check: 412.5 + 87.5 = 500. So far so good.
Extract Potential of Grains used:
Pilsner Malt 38
CaraPils 33
System mash efficiency for lagers is 66%.
3. Pounds of each needed: (Ingredient Gravity / Gravity per lb. malt / mash system efficiency)
Pilsner Malt: 412.5/38/.66 = 16.44 lbs.
CaraPils Malt: 87.5/33/.66 = 4.01 lbs.
So when I plug these grains and amounts into ProMash, it calculates the % of Grist bill and shows:
Pilsner Malt = 80.4%
CaraPils = 19.6%
I checked the percentage of each malt using good old algebra: 16.44lbs is 80.4% of 20.45lbs. and 4.01 is 19.6% of 20.45lbs. So the algebra matches the ProMash calculation.
What gives? |
Milan Bartolec
Junior Member
Username: Littlebro
Post Number: 84
Registered: 03-2003
| | Posted on Tuesday, December 21, 2004 - 06:11 pm: |
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By the way:
The settings I have in the recipe for promash are: Potential = 66% and Promash does come up with the exact Estimated OG of 1.050. |
Bill Pierce
Moderator
Username: Billpierce
Post Number: 1558
Registered: 01-2002
| | Posted on Tuesday, December 21, 2004 - 06:18 pm: |
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The answer lies in the difference in extract potential between the two malts. In one case (ProMash) you are calculating the percentage of the grist based on the weight of each malt. In the other (Daniels) you are calculating the percentage of the sugars each contributes to the wort. There is a difference because the pilsner malt has a higher extract potential (1.038) than carapils malt (1.033). |
Milan Bartolec
Junior Member
Username: Littlebro
Post Number: 85
Registered: 03-2003
| | Posted on Tuesday, December 21, 2004 - 06:35 pm: |
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that makes perfect sense. Thank you Bill.
So... is there a standard when reading brewing material as to what is being used for the %? (extract vs. weight). If a book states, that malt xyz should be used in upto 15% of the grist bill, how do I know whether they are talking about 15% weight, or 15% extract potential?
I would assume in Mr. Daniels book that when he gives recipe guidelines he is using extract potential. |
Bill Pierce
Moderator
Username: Billpierce
Post Number: 1560
Registered: 01-2002
| | Posted on Tuesday, December 21, 2004 - 06:41 pm: |
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I'm used to thinking of the malt contribution in terms of the weight rather than of the extract. But that doesn't make me any more "right" as long as we're comparing apples with apples. |
dave star
New Member
Username: Dave_star
Post Number: 1
Registered: 12-2004
| | Posted on Wednesday, December 22, 2004 - 04:36 pm: |
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Heirs the way I enter % in pro mash. I just enter the % as the number of # then adjust the batch size till I get the gravity I want then I click the box next to lock ingredients to batch size and adjust the size to what I want. As an example with your recipe I would enter 82.5 # of pils and 17.5# of Cara-Pils then I would adjust the batch size to 49 gal and check the lock ingredients to batch size box and set the batch size to 10 gal. This gives me 16.84 # pils and 3.57 # Cara-Pils. I hope this helps
Dave |
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