Thanks for all the replies chaps. Lots of useful info there.
RdeVjun, yes I am planning a BIAB brew.
Seems like a lot of water, I think im gonna need a bigger pot!
Any idea how many Litres I can expect to lose if im trying to make a 25ltr brew? I have a figure of 30% in my head for some reason.
Cheers
Stu
Bingo! I thought as much Stu.
If it were me, I'd look to do a no- sparge BIAB to begin with, you can look at other alternatives later. Nick has mentioned batches bigger than the pot volume, sure that's a possibility, but to start with I'd do a straight no- sparge/ full- volume batch until you get your head around mashing and the mechanics of it all. Don't worry too much about your pot size, even if you've just got a 19L big double ewe stockpot, rest assured you can make much larger batches than that, just get whatever size you can afford. Here's a rough, simple guide:
Whatever your pot volume is, divide it by 6, that'll give you the kilos of grain you'll add. A bit more than half of the pot volume should end up being the brewlength (i.e. beer in bottles/ keg), that's realistic if you've never done this before, anything above that is a bonus*. So, prepare 1/6th of the pot volume in kilos of grain, fill the pot 2/3 full with water, bring it to the mashing temp + 4degC, then put the bag in, rain in the grain while stirring. Top up the pot with more water at the mash temp until it is full (you can also fine tune the mash temp with this top up water), insulate the pot and leave for at least 60 minutes. Lift the bag out and put the pot on the heat for the boil, drain the bag into a bucket (add drainings to the boil), suspending it from a cupboard/ door handle works fine. Boil the liquor (the pot should be at least 3/4 full), adding hops as per the recipe. Chill the pot in a laundry tub, pour through a sieve into the fermenter at pitching & happy days- welcome to All- Grain brewing!
This method probably isn't the most efficient and is fairly conservative, but greater efficiency will come with experience, with sparging and so on.
It doesn't get much simpler than this method but it is really only the beginning as far as BIAB goes, while your simple BIAB bag and stockpot can do just about anything achieved with another method, be it sparging, mashout, step mashing, decoction, cereal mash, over- gravity, partigyle etc. To get more brewlength out of this system (eg. the 25L you are after), basically you just add more grain, so reducing the grain to water ratio, but also by dunk sparging for some second runnings which will increase your efficiency but also make up for the extra grain absorption losses, plus by post- boil dilution. If you brew a sugar- friendly style (eg. ESB), the bigger volumes are easier to achieve... or you can just get a bigger pot!
Losses aren't that easy to predict until you try it on your setup, depending upon what your reference volume is, i.e. brewlength, post- boil volume etc, this method loses about 1/4 to 1/3 of the total volume in evaporation and grain absorption, but there are some sneaky ways to minimise that too.
Sorry for the epic essay, hope this helps! :icon_cheers:
* As Nick mentions, it is easier to thin than to thicken, this guide should give you a higher SG than your recipe needs, in the interests of simplicity just dilute it back to the target SG at pitching with cold, sanitary water (i.e. town water, not untreated rainwater).