I've been working on a new version of this calculator, which implements all the necessary machinery to do Maxi-BIAB calculations... but that's not the point of this post
I did another brew on the weekend and was very happy with the results (and the brew!)
I decided to redo my Hefeweizen (50/50 Wey Pils/Wheat), but this time with a 5 step mash. Well, the mash makes no difference.
Conversion Efficiency = 99% (which I think should be the default)
Real Absorption = 1.3L (range seems to be 1.2 to 1.4L depending on how agreesively you squeeze, and the coarseness of your grind)
I set my 90 min evaporation to 9.38L, which is based on 6.25L/hr, which is what my BeerSmith 2 is set to. I suspected my evaporation is actually closer to 10L over 90mins, but I'd rather underestimate evaporation, than overestimate
New Settings
Do You Cube Your Wort? Yes
Kettle Loss = 3L
Cube Loss = 2L
Mash Tun Limit = 49
Start of Boil Limit = 40
End of Boil Limit = 40
Cube Limit = 23
(note, all of those new figures are hidden by default, and in reality the limits aren't needed for my equipment with a single batch)
And then the Brew Requirements
Desired Fermenter Volume = 21L
Desired Fermenter OG = 1.050
And Sparge Water = 0L
I already have the Wey Wheat and Pislner grains entered, and the average potential for the grainbill is 78.25%
CE Calc tells me
Grain Bill = 5.210KG (2.605 of each grain)
Total Strike Water = 39.31L
Total Mash Volume = 42.96L
Liquor to Grain Ration = 7.54 L/KG
And my expected results are
Expected Start of Boil Volume (100C) = 36.42L
Expected Start of Boil Gravity = 1.037
Expected Into Boil Efficiency = 83.0%
Expected End of Boil Volume (100C) = 27.04L
Expected End of Boil Volume (20C) = 26L
Expected End of Boil Gravity = 1.050
Expected Into Fermenter Efficiency = 67.00%
Nice round numbers
...
Now for my next trick, I wanted to update my recipe in BeerSmith, and see how everything scales... My original recipe was a triple batch maxi-biab!
So, I updated my equipment profile a little bit... Most was already the same
Brew House Efficiency = 67% (based on the CE Calc Into Fermenter number)
Mash Tun Volume =49L
Loss To Trub and Chiller = 5L (3L in Kettle + 2L in cube, same as ce calc)
Batch Volume = 21L, same as CE's Desired Fermenter Volume
Fermenter Loss = 2L (irrelevant really)
Boil Off was already 9.38L for 90 mins, which gave a Boil Volume of 36.41L, which is remarkably similar to the the 36.42L predicted by the CE Calc
I then applied this new equipment profile to the recipe... and adjusted the grain to 5.2KG
BS2 is then predicted a Mash Efficiency of 83.0%... hey whatdya know, exactly the same as CE Calc...
It also predicts 39.51L of strike water... which is just 100ml more than the CE Calc prediction. This is because BS2 is using a different absorption figure, which I have left at the default
BS2 is predicting 42.98L for Mash Volume, CE Calc is predicted 42.96L, that's the extra 100ml I guess, but close enough
BS2 is predicting 27.04L post boil volume, which is the same as the CE Calcs...
So, basically, all volumes are predicted as the same...
where it gets interesting is BS2 is predicting an OG of 1.052 and CE Calc is predicting 1.050.
Hmmmm... we have a contest
Which brewing software will be right
Soooo, I did the brew
I mashed in at 35C, and measured the volume, 43.2L, which is close enough to the 43L predictions...
Measured Start of Boil Volume was 36.3L, just 300ml off the target... well within my margin of error...
(Absorption was 1.32L instead of 1.3L/KG!)
Gravity was 1.037, as predicted, interestingly this indicates a conversion efficiency of 98.5%... but if I had 1.0372, then it would've been 99%... so that shows you, the limit here is the accuracy of my hydrometer. Or another way, 0.2SG points = 0.5% conversion efficiency
End of Boil Volume = 26.5L, when we were aiming for 27.04L, so 500ml off, which is because I underestimated evaporation.
Actual evaporation was 9.8L instead of 9.38L
Gravity = 1.051, which means a final Kettle efficiency of 92.9% which is close enough to the predicted 83%
So... If I added another 500ml into the pot, then it would've been the 1.050, and the efficiency figures and conversion figures etc were exactly spot on.
NOTE: I did NOT use 83% efficiency to calculate the grain bill
But BeerSmith 2 did... and BS2 was predicting 1.052... where as I really did get 1.050 at 27L, or 1.051 at 26.51L
So, that's another tick to the CE Calcs numbers
Based on my full cube and my 3L of trub, I should get 21L into the fermenter at 1.051, and if I do that, the CE Calc is telling me I should add 420ml of water to the fermenter.. which I probably won't... I wanted 1.050-1.052 anyway!
End result... the CE Calc was pretty much spot on. BeerSmith 2 was not, and I was only out by how far out my evaporation estimate was.
Every test I have done has shown that the methodology used by the CE Calc is correct and its results are correct, and it does not vary based on magical BrewHouse or Kettle Efficiency numbers.