Thirsty Boy
ICB - tight shorts and poor attitude. **** yeah!
- Joined
- 21/5/06
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I'd start with a much more "normal" l:g ratio. Think about your sparges. I'd be aiming for 1 sparge of the first grist, and 2 spurges of the second grist. So you need 4 separate quantities of water. Remember also, that although you will have a normal volume in your pot, you have used an abnormally large amount of grain... So you will have more trub than usual etc.
The way to do it, is to initially plan the brew as though you had a much bigger pot and you were going to do it all at once in there. So calculate water, losses, trub - as if it were all one big arsed batch, then split your volumes to give you what you want.
For instance: say you wanted to start your boil with 38L (you are planning to boil down to your final volume, even though that might take 2 hours)
So given say 10kg of grain, and losing 0.5 L/kg... You will need a total of 48L.
You'll have to mash with at least 22L for 10kg of grain - which leaves you with 26L to use as sparge. And I would be inclined to split that up into 10L to sparge the first grist once & 2 sparges of 8L each for the second grist.
Of course, because you will need a long boil anyway....you can always sparge with more than that and keep it aside to add to the boil as it progresses. Doing that will allow you to mash with a little more water too if you want.
The more your sparge, the more efficient it will be, but the longer the boil will need to be to get down to volume. Eventually you get to the ultimate level of pointlessness, where you could simply have done two separate 5kg mashes, boiled them down to half volume and combined the two worts in the fermenter.
So somewhere in between is a "reasonable" compromise between extract efficiency and time efficiency.. You'll have to decide where it is.
Cheers
TB
Edit - spelling and PS
PS - remember, you don't need to mash the first grist for very long. As long as it's properly hydrated and the starch has been given a chance to gelatinize and dissolve... You are good to stop. You aren't bringing anything to the boil, the enzymes are all still there, they will keep working for the duration of both mashes. If anything, better because you are adding a fresh batch of new enzymes part way through. 15, 20 minutes and get that thing out of there, get your new one in and start sparging the first one, it might be a little starchy... But when you add it back to the mash... The enzymes in there will fix it up. Let your second mash complete properly though. I would mash out the second one to help with efficiency (direct heat, so no need for infusion water) the first one doesn't need it because once again, you will be recombining it's run-off with an enzymatically active second mash anyway.
The way to do it, is to initially plan the brew as though you had a much bigger pot and you were going to do it all at once in there. So calculate water, losses, trub - as if it were all one big arsed batch, then split your volumes to give you what you want.
For instance: say you wanted to start your boil with 38L (you are planning to boil down to your final volume, even though that might take 2 hours)
So given say 10kg of grain, and losing 0.5 L/kg... You will need a total of 48L.
You'll have to mash with at least 22L for 10kg of grain - which leaves you with 26L to use as sparge. And I would be inclined to split that up into 10L to sparge the first grist once & 2 sparges of 8L each for the second grist.
Of course, because you will need a long boil anyway....you can always sparge with more than that and keep it aside to add to the boil as it progresses. Doing that will allow you to mash with a little more water too if you want.
The more your sparge, the more efficient it will be, but the longer the boil will need to be to get down to volume. Eventually you get to the ultimate level of pointlessness, where you could simply have done two separate 5kg mashes, boiled them down to half volume and combined the two worts in the fermenter.
So somewhere in between is a "reasonable" compromise between extract efficiency and time efficiency.. You'll have to decide where it is.
Cheers
TB
Edit - spelling and PS
PS - remember, you don't need to mash the first grist for very long. As long as it's properly hydrated and the starch has been given a chance to gelatinize and dissolve... You are good to stop. You aren't bringing anything to the boil, the enzymes are all still there, they will keep working for the duration of both mashes. If anything, better because you are adding a fresh batch of new enzymes part way through. 15, 20 minutes and get that thing out of there, get your new one in and start sparging the first one, it might be a little starchy... But when you add it back to the mash... The enzymes in there will fix it up. Let your second mash complete properly though. I would mash out the second one to help with efficiency (direct heat, so no need for infusion water) the first one doesn't need it because once again, you will be recombining it's run-off with an enzymatically active second mash anyway.
