Check My Degrees Plato Calculations

Question

I'm putting together my own brewing calculations spreadsheet to develop a good understanding of the ins and outs of building a beer recipe. For my malt/mash calculations, I've chosen to use the degrees Plato scale because it makes sense to me.

Can someone smarter than I please check my assumptions/calculations? They are as follows:

Degrees Plato = Extract Weight (in kg) / Total Wort Weight (in kg) * 100

Where, Total Wort Weight = Total Extract Weight (in kg) + Water Weight (in kg)

Recipe

Brewhouse Efficiency: 75%

Wort Volume = 32.4 l

Water Weight ~ 32.4 kg (approximation, good enough here)

Malt 1 - Bestmalz Pilsner

Extract Fine Grind 80.5%

Weight Used: 5 kg

Extract Weight = 5 kg * 80.5% * 75% = 3.02 kg

Malt 2 - Bestmalz Caramel Hell

Extract Fine Grind 75%

Weight Used: 1.5 kg

Extract Weight = 1.5 kg * 75% * 75% = 0.84 kg

Total Wort

Extract Weight Total = 3.02 kg + 0.84 kg = 3.86 kg

Water Weight = 32.4 kg

Total Wort Weight = 3.86 kg + 32.4 kg = 36.26 kg

Therefore, Degrees Plato = 3.86 kg / 36.26 kg * 100 = 10.65 deg P ~ 1.043 SG...

Does this sound right? Any help is much appreciated!

Answer 1

That all looks correct to me. Well done.

P.S. Gosh... I haven't calculated a recipe by hand like this for many years. I used to do so a long time ago, when I first adopted homebrewing software (I use StrangeBrew 1.8). But I also understand the want or need to develop your own spreadsheet, and cheers to that! (I love Excel. I live in Excel. I've used it for other calculations like pre-boil post-boil post-ferm volume calculations, where other softwares have failed to consider every variable. And that's just one example of many. :) )