Grainfather App liquor volumes, wtf?

Brett74 · Aug 18, 2016

I have just finished my first two AG brews on my GF and was less than impressed with the OG I attained, started playing with the numbers and suspect the problem lies in my liquor calcs. I used the GF app. instead of the recipe from Greg Hughes calcs. The differences were quite big, I had a recipe with 6,1 kg of grain for 17 liter batch, an imperial IPA, GF app said 23,3 liters for the mash and 5 liters for the sparge. That obviously didn't work out so good...feel stupid for not double checking these volumes...am I missing something ??
On Monday I am planning one of Greg's single hop Ales, there is 4,94kg of grain so for a 23 liter batch according to:
Greg 12,3 liters Mash and 19,7 liters sparge.
Grainfather App 16,8 liters Mash and 15,6 liters sparge.
Grainfather calc. from their website 14,3 mash and 16,9 sparge.

Feeling a little lost so it's OK if you talk to me like I am dumb....
My goal is to get my efficiency up so I presume the way forward is to figure out how little mash water is doable?

Slid · Aug 18, 2016

Brett74 said:
I have just finished my first two AG brews on my GF and was less than impressed with the OG I attained, started playing with the numbers and suspect the problem lies in my liquor calcs. I used the GF app. instead of the recipe from Greg Hughes calcs. The differences were quite big, I had a recipe with 6,1 kg of grain for 17 liter batch, an imperial IPA, GF app said 23,3 liters for the mash and 5 liters for the sparge. That obviously didn't work out so good...feel stupid for not double checking these volumes...am I missing something ??
On Monday I am planning one of Greg's single hop Ales, there is 4,94kg of grain so for a 23 liter batch according to:
Greg 12,3 liters Mash and 19,7 liters sparge.
Grainfather App 16,8 liters Mash and 15,6 liters sparge.
Grainfather calc. from their website 14,3 mash and 16,9 sparge.

Feeling a little lost so it's OK if you talk to me like I am dumb....
My goal is to get my efficiency up so I presume the way forward is to figure out how little mash water is doable?

So you have a 5kg grain bill for a GF brew.

My advice, which is second hand from a member pcz (I think) is to use ~3.5L per kg of grain and this works very well for the 5-6kg grain bills I use my GF for.

As regards the sparge water, you calculate how much you need in total by adding up the volume you want in the FV, plus the water absorbed by the grain (number of kilos of grain x 0.8 gives you the number of litres) plus dead space and boiling losses (about 5-6L). The sparge water is enough to make up the mash water to the total.

Badseed1974 · Aug 18, 2016

I use the calculator on the GF website and it's always spot on for me.

Slid · Aug 18, 2016

http://www.thehomebrewforum.co.uk/showthread.php?t=61335

This is the link to pcz's advice. I learned a great deal from this, so I cannot recomend it too highly.

Brett74 · Aug 18, 2016

Great post you linked to, thanks!

DoctorMick · Aug 20, 2016

A total of 28l for a 17l brew is way too much. Strange that the app says that, the calculator on the GF website says 19.97 mash and 6.91 sparge for a 17l batch. How much did you end up with in the fermenter? It should have been well over 17l.