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Wez

Landlord.
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I'm planning on brewing my first BIG BATCH at the weekend which will hopefully leave me with 70L of 1.042 beer.

I wondered if anyone has the time would they check my math for calculating required volume in the boiler pre boil?

First, some information about my system and it's losses and the ingredients that I'll be using:

Batch Size 70L
%ge lost to boil 15% - this has been all over the place from 16% to 28% over 90 mins – so going with a 60min boil and calculating 15%
Weight of hops to be used 240g
Expected loss to hops = ~1.5L (based on 240 x 0.006L)
Boiler dead space = 3L

I calculate that I will need a pre boil volume of ~88L

I calculated this by adding together required volume in FV, loss to boiler and loss to hops, so 70L + 3L + 1.5L = 74.5L then dividing this by 85 (which is the %ge amount I wont loose to the boil) then multiplying by 100 .. giving 87.6L

Is that right?

Also – I am certain that I will not collect 88L before the gravity of the runnings from the mash hit 1.008 so I expect that I will have to top the boiler up to 88L with tap water – which I will treat with campden tablet. - Is this a practice that other people do?

Cheers!
 
Enough about brewing. What about your boil :shock:


:lol:
 
I never bother measuring boil lose ect tend to use Promash these days it does it for me but i don't really need to measure liquids anyway as i know my system inside out anyway.One thing i notice is you are sparging down to 1.008 i used to do this but over the years i have learned to sacrifice efficiency in favour of better beer when i sparged i would stop when i reached about 1.0015 now i batch sparge. :party:
 
MEB said:
Enough about brewing. What about your boil :shock: :lol:
:rofl:
Wez, the math looks right but I guess the proof of the pudding will be when you try. As for topping up, I tend to top up the boiler with pre-boiled water from the kitchen kettle as the boil goes along. I only do 23L batches and top up either 2 or 3 kettles (to keep the level in the boiler about where I need it from experience).

Good Luck :thumb:
 
I would be VERY CAREFUL Wez,
On the 100ltr pots 0.5cm = 1ltr roughly, and the pots are only 99ltr not 100ltr
88ltrs will give you 5.5cm room for the turbulent boil...I wouldn't feel safe doing that.
Mine gets quite close to spilling over with 76ltr and that's with 12.5cm spare.

If you do 88 ltr I would be very tempted to wrap something around the element to lead connection JIC.
 
MEB - :lol:

Rab - Yep, quite right I am going to start stopping the sparge at 1.020 or 1.015 again :thumb:

Buzz - Yeah I'm going to go for it, using a kettle full at a time I think as you say ;)

Vossy - Good advice, would you say that a 60L brewlength is more suitable from the 100L boiler?
 
This is a 76ltr boil in a 100ltr pot. The small wort ridge at the back is about 3-4cm from the lip, but the wort folds in the centre are a fair bit higher...but they start at the edge...I just caught the boil at a quiet mo!

CIMG0413.jpg


76-77ltrs gives me a post boil of 60ltr depending on the amount of hops used.
 
Cheers for the pic

I find that with FWH I don't have to worry about the boil foam up, the hops sort of kill that, I need to have a play with the numbers again - might reduce to 60L
 
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