Loss to the boil/grains (etc)

[Andyhull]

Probably a stupid question here,

How do you calculate the amount of liquer needed?
What i mean is how do you know how much liquer will be need from start to finnish, loss to grains, boil off and how do you know how much sparge water to add to to end up with 23lt's of wort?

Andy

 

[zgoda]

You have to know your evaporation rate. Start with 8% and modify accordingly. This is specific to every brewhouse.

Grain absorbs just bit over its weight, i'm assuming 1.1 litre/1kg.

Theres aplenty of calculators online and for mobile phones, eg. Brewzor for Android.

 

[Andyhull]

Sory, hopeing not to sound too thick.
Is that 8% from the wort once the grains have taken their 1.1lt per kg

 

[zgoda]

Yes, this is 8% of the wort in copper (evaporation during the boil), so after deducting what was left in grain bed. You have to account additional 4% loss of volume for thermal shrinkage of liquids during cooling.

BTW, this is 8% per hour, not total.

 

[Andyhull]

:cry: this is complicated

 

[zgoda]

:cry: this is complicated

That's why calculators exist.

 

[Andyhull]

Thanks for the responces zgoda.

I'll have a good look around.

Im not planning on going AG for a couple of weeks or so so i'll have plenty of time to get my head around it :

 

[Good Ed]

Ok, I'll go through my last brew which was for 23L; 23L + deadspace of HLT 1.3L + absorption and displacement of hops (100g = 1.6L) I had 174g of hops which equals 2.8L + evaporation (as zgoda says start with 8% and then adjust) I use 9%, which is per hour, so for 90mins boil = 4.4L + allowance for liquor volume decreasing in volume from 100C to 20C = 1L. So with all that to get 23L my pre boil volume (what you want to collect from sparging) is 23 + 1.3 + 2.8 + 4.4 + 1 = 32.5L

It's not an exact science and some brews are over and some under, but it's a good guide. I only have a 30L boiler, so what I do is put the balance in a pot on the stove at a simmer and add to the HLT when the boil has reduced a bit.

 

[Dave1970]

It's not that bad Andy

Once you've done 1 or 2 brews you'll know what your setup does

For me I know I need 30 litres pre-boil to end up with 23 litres in the FV (this is for a 90 min boil). This is probably quite a lot of loss because the electric boiler I use has a very vigorous boil. Given this the rest is easy...

fill HLT to 40l add campden tablet,
get the mash on @ 2.5 litres per kg of grain
half hour before end of mash stick a bit more water into HLT, I don't worry too much about exactly how much but topping back up to 30 litres is going to be enough
Fly sparge until I've got 2x15 litres in 2 FV's (I do check gravity isn't dropping below 0.990 but this hasn't happened yet)
Drain off anything left in the HLT
Pour the 2 FV's into the HLT (which is also my boiler) and get the boil going

apart from maybe a bit of wasted electricity heating a bit more water than I need this works fine without worrying about any volume calcs apart from the 2.5 x KG for the mash. I do find it's well worth using a calculator for the mash water temp makes it much more likely that you'll hit your target mash temp.

 

[hairybiker]

Yes it is easier to calculate after you have done a few brews.
I tend to use gallons so my base is:-
3.5 gal in to MT with 5-6Kg of malt
sparge with 4-5 gals to get 6.5-7 gals in the boiler
this gives me 5 gals in the fv after boil/cooling etc.

Don't you just love the mixed measurements
(When I grew up we started on Imperial measurements & money, then they introduced decimalisation and I tend to switch units as needed, I still use mpg in the car rather than lpk or lpm :thumb: )