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Hey forum users and developers. Hopefully this is helpful and thorough!
In order of ease of implementation:
The conversion formula is properly defined as the total amount of extract available from your grains, the potential extract, to the amount of sugar converted from the mash. The most accurate method for this involves tracking the weight of extract/sugar converted during the mash, the mass of the wort, and the plato of the wort. However the calculations are more complicated than the simplified “total gravity point” method we’re all found of. See Braukaiser for more information.
However the traditional total gravity point method fails to capture one fundamental aspect crucial to conversion efficiency, that wort volume is greater than water infusion volume. Which is significant enough that the typical ~1.055 SG recipe will produce around ~9% more wort volume, which is due to dissolving starches being converted to sugars, as well as proteins, beta glucans, etc etc.
I’m not aware of an accurate method of using the gravity point method for a conversion efficiency calculation.
In order to get the Conversion Efficiency, we need the following information (From Braukaiser):
Tl;dr Editable google sheet
Apologies if the below is hard to follow, math formulas don't seem to be supported on the forum.
Situation: 12 lbs, 37 PPG. 7.6 gallons of water. Mash wort measured at 1.043 sg
A) The Maximum theoretical First Wort (FW) extract, which is proportional to the degree plato.
FWmax= 100*[ Mass_Grain(kg) * e_Grain (extract % dry basis) ] / [ MashWater(L) + Mass_Grain(kg)* e_Grain(extract % dry basis) ]
FWmax=100 * [ 12 (lb) * 0.45359237 (kg/lb) * 37 ppg / 46 ppg ] / [ 7.6 (gal) *3.785411784 (L/gal) + 12 (lb) * 0.45359237 (kg/lb) * 37 ppg / 46 ppg ] = 13.2081793 °Plato
B) The measured first wort plato
FWMeasured=-616.868+(1111.14*SG)-(630.272*SG^2)+(135.997*SG^3) = 10.71605614 °Plato
Then we can calculate the efficiency directly using the ratio of measured to maximum % extract by weight.
Conversion Efficiency =100*(FWMeasured / FWmax) * (100-FWmax) / (100-FWmeasured) =78.8674 %
Currently brewersfriend uses the simplified total points method, and incorrectly attributes it using the strike water volume, leading to a percent error of 6.67%.
Incorrect Conversion = 1000 *(SG-1)*VWaterMassGrain * PPG=1000 *(1.043-1)*7.612 *37=73.60%
In order of ease of implementation:
- Personally I would remove the row where ppg is currently listed, as it’s more properly used as a grain property rather than a wort property.
- Still getting the invalid input as a red border for decimals that aren’t 0.5 multiples on firefox (windows), but not chrome.
- Then I would add a row for Total grain weight, and average PPG below the grain table, similar to where total grain weight and average DP is listed in the complete recipe builder.
- I would also add a column of grain PPG or similar to the right of the grain name, as this is rather important for efficiency calculations.
- The calculator name should probably change to “efficiency” calculator, as it works for any component of efficiency (conversion, lauter, mash, or brewhouse) and not just brewhouse.
- The user input for Wort volume needs to change to something along the lines of "Total mash/infusion water volume" when the conversion efficiency is selected.
- I would probably change the terms for the types of efficiency to be in line with the standard definitions, see Braukaiser for more info. Something like the following
- Pre-Boil to “Mash: Pre-Boil”
- Ending Kettle to “Mash: Post-Boil”. Both should result in the same efficiency number.
- “Brew House” to “Brewhouse: Fermenter”.
- Pre-Boil to “Mash: Pre-Boil”
The conversion formula is properly defined as the total amount of extract available from your grains, the potential extract, to the amount of sugar converted from the mash. The most accurate method for this involves tracking the weight of extract/sugar converted during the mash, the mass of the wort, and the plato of the wort. However the calculations are more complicated than the simplified “total gravity point” method we’re all found of. See Braukaiser for more information.
However the traditional total gravity point method fails to capture one fundamental aspect crucial to conversion efficiency, that wort volume is greater than water infusion volume. Which is significant enough that the typical ~1.055 SG recipe will produce around ~9% more wort volume, which is due to dissolving starches being converted to sugars, as well as proteins, beta glucans, etc etc.
I’m not aware of an accurate method of using the gravity point method for a conversion efficiency calculation.
In order to get the Conversion Efficiency, we need the following information (From Braukaiser):
Tl;dr Editable google sheet
Apologies if the below is hard to follow, math formulas don't seem to be supported on the forum.
Situation: 12 lbs, 37 PPG. 7.6 gallons of water. Mash wort measured at 1.043 sg
A) The Maximum theoretical First Wort (FW) extract, which is proportional to the degree plato.
FWmax= 100*[ Mass_Grain(kg) * e_Grain (extract % dry basis) ] / [ MashWater(L) + Mass_Grain(kg)* e_Grain(extract % dry basis) ]
FWmax=100 * [ 12 (lb) * 0.45359237 (kg/lb) * 37 ppg / 46 ppg ] / [ 7.6 (gal) *3.785411784 (L/gal) + 12 (lb) * 0.45359237 (kg/lb) * 37 ppg / 46 ppg ] = 13.2081793 °Plato
B) The measured first wort plato
FWMeasured=-616.868+(1111.14*SG)-(630.272*SG^2)+(135.997*SG^3) = 10.71605614 °Plato
Then we can calculate the efficiency directly using the ratio of measured to maximum % extract by weight.
Conversion Efficiency =100*(FWMeasured / FWmax) * (100-FWmax) / (100-FWmeasured) =78.8674 %
Currently brewersfriend uses the simplified total points method, and incorrectly attributes it using the strike water volume, leading to a percent error of 6.67%.
Incorrect Conversion = 1000 *(SG-1)*VWaterMassGrain * PPG=1000 *(1.043-1)*7.612 *37=73.60%