Suggestion: How to Batch Sparge

[Moley]

Now I’m not a thicko, but when I was looking at crossing over to AG it still took me a while to understand BrewStew’s guide, the losses and dead spaces, volumes and temperatures for sparging. As I did my first couple of brews, then it made sense.

However, I still don’t really understand batch sparging and can’t find anything to explain how it’s done or how to use the forum’s calculator.

Have I missed something? Is there already a guide?

I think that would be a useful thing to have, so I’m probably going to ask stupid questions from the position of a total numpty until I’ve sussed it well enough to write a guide, unless someone else wants to do that.

Help me to understand this, and let’s use round numbers:

I want to end up with 25 litres
I expect to lose 15% to evaporation
Loss to hops & trub inc. boiler dead space will be 1.5 litres
I’m using 5kg of grain
Mash tun dead space is 1 litre
Water:Grain ratio 2.5 litres to 1kg

Calculated Wort Volume is 31.2 litres - that’s what needs to go into my boiler.
85% x 31.2 = 26.5 litres - that’s my final 25 + the 1.5 left in the boiler.
Total volume of water = 37.2 litres - this assumes 1 litre lost per Kg of grain + tun dead space.

So I want 31.2 litres of wort, or two batches of 15.6 litres.
First batch I need 21.6 litres, which is 15.6 + absorption by grain + dead space.

12.5 litres (5kg x 2.5) @ 78°C goes into the tun.
5kg grain goes in
Equalise temperature at 68°C
Lid on, leave for 90 minutes.

Here’s where I lose the plot:
12.5L has gone in but I’m only going to get 6.5L out, so that’s where the 9.1L top-up comes from.

Does that 9.1L go in at the end of 90 minutes? At 68°C ? Stir?

Recirculate first runnings, drain the tun?

Seconds batch, 15.6 litres because the losses are already taken care of.

What temperature? Stir? Leave to stand? How long for?

Recirculate and drain?

Why only two batches, could I do three?

31.2 ÷ 3 = 10.4

First batch 16.4 (12.5 + 3.9 top-up)
Second batch 10.4
Third batch 10.4

How do I know what I can get out of 5kg of grain? If I tell the calculator I want 50 litres from 5kg of grain it doesn’t come back and say “hang on Sonny Jim, you can’t do that.”

 

[BigYin]

no wonder you've lost the plot with it - I'm confused as hell reading that too :lol: :lol: :lol:

I fly sparge, never done a batch sparge, so can't help :whistle:

 

[Dunfie]

Here’s where I lose the plot:
12.5L has gone in but I’m only going to get 6.5L out, so that’s where the 9.1L top-up comes from.

Does that 9.1L go in at the end of 90 minutes? At 68°C ? Stir?

Recirculate first runnings, drain the tun?

Seconds batch, 15.6 litres because the losses are already taken care of.

What temperature? Stir? Leave to stand? How long for?

Recirculate and drain?

Why only two batches, could I do three?

31.2 ÷ 3 = 10.4

First batch 16.4 (12.5 + 3.9 top-up)
Second batch 10.4
Third batch 10.4

How do I know what I can get out of 5kg of grain? If I tell the calculator I want 50 litres from 5kg of grain it doesn’t come back and say “hang on Sonny Jim, you can’t do that.”

Good idea M, all the logic and arithmetic is fine. I can fill in the gaps using my own method and unfortunately part of my process is from information I have read but cannot pinpoint the sources at present.

You have completed the mash using the calculated mash water and need to top up.

- Heat up your sparge water to between 75C-80C. You want to use water that is hot enough to stop the enzymatic activity but not too hot so that you begin to leech the tannins out of the grain.

- Add the top up liquor, stir in and leave to rest for a few minutes to ensure it is mixed.

- Before draining into a fermenter, recirculate a few litres of wort by running into a jug and then carefully pouring back over the mash (it is useful to place some perforated tinfoil on top of the mash as you recirculate).

- Allow to drain back into the fermenter once there are no obvious pieces of grain coming through.

- Once draining add your second batch with water that is still between 75C-80C, stir and leave for a few minutes and repeat the draining exercise that you performed in the first batch.


Why do we only use two batches?
There has been some batch sparge experiments performed in US and they concluded that sparging to get two equal measures of wort is the most efficient (I will have to look for the source of this information).


How do I know what I can get out of 5kg of grain?
There is a laboratory maximum that you can extract from grain. Each variety of grain and sugar will have a separate maximum eg Pale Malt is around 300-305, sucrose is 360). The measure that we use to calculate how much we can extract is Litre Degrees per Kilogram (LDK). So for example, if we extracted the maximum amount of sugar from Pale Malt with an LDK value of 300 into 1 ltre of water we would have a solution with a gravity of 1300.

So, by doing some arithmetic and using your example for 5kg of pale malt in 50 litre:

OG = (Grain in KG * LDK Value) / (Brew Length)

OG = (5 * 300) / 50

OG = 30 (1030)

However we need to factor is our own efficiency rating for this. I personally work to around a 72% brewhouse efficiency so I would expect to get 50l @ 1021.6

 

[Vossy1]

M, do you want to finish this off or is it scrap ?...seems a shame to waste it.

 

[Moley]

It would seem a shame to bin it, although I can't see myself doing anything with it at the moment. Leave it for now.

 

[Vossy1]

Thanks M :thumb:

 

[Aleman]

Here’s where I lose the plot:
12.5L has gone in but I’m only going to get 6.5L out, so that’s where the 9.1L top-up comes from.

Does that 9.1L go in at the end of 90 minutes? At 68°C ? Stir?

Yes . . . anywhere between 68 and 78C . . . Stir to mix it in and extract some sugars.

Recirculate first runnings, drain the tun?

Correct

Seconds batch, 15.6 litres because the losses are already taken care of.

:thumb:

What temperature? Stir? Leave to stand? How long for?

Again anywhere between 68 and 78C . . . I am for around 72C . . . Yes Stir to equalise the sugar concentration, rest for 10-15 minutes

Recirculate and drain?

Yes

Why only two batches, could I do three?

You can do three, but teh returns (increase in efficiency) are not very large. The only time that doing 3 batches is if you have restricted space in your mash tun for the gravity of the beer you are brewing.

31.2 ÷ 3 = 10.4

First batch 16.4 (12.5 + 3.9 top-up)
Second batch 10.4
Third batch 10.4

Remember that you want equal volumes out for each batch

How do I know what I can get out of 5kg of grain? If I tell the calculator I want 50 litres from 5kg of grain it doesn’t come back and say “hang on Sonny Jim, you can’t do that.”

Actually you can do that . . . your preboil wort will be very dilute though. Basically you run your recipe through a calculator that tells you how much grain to use for a given volume and gravity . . . and then you put those figures into the batch sparge calculator to calculate the amount of liquor to use.