Thanks I was looking for this kind of answer just a typical amount of starting water needed.So I believe for 10 liter batch 20-25 liters is needed.
no, not that much. Its
not as simple as 33L - 19L = 14 ... so for a 10L batch you want 10+14 = 24. Does not work like that. The amount of water is proportional to your grains etc. Here's how I work out water for BIAB.
For a 10L batch of normal beer it would be somewhere near:
12.5 + 1.25 + 2.0 = 15.75L ... when you put your grain into that it will have a volume of around 17.75L so you could make this in a 20L pot.
How did I work it out ..
12.5 = The volume of wort left in your kettle after the boil - you have to have enough left to leave behind break material, hops etc in the kettle and still put as much as you want into your fermenter. So if I want 10L of finished beer, I will lose about 0.5L to yeast at the bottom of the fermenter, I will lose about 1.5L to the trub and hops in the bottom of the kettle, and the hot wort itself will shrink as it cools, costing about 0.5L - this adds up to 2.5L. Therefore 10+2.5=12.5L is how much wort I want to have sitting in my kettle when I turn off the flames.
1.25 = this much beer will use about 2.5kg of grain, you soak it in water, dissolve some stuff out of it, squeeze out you bag... and whats left over in the bag, absorbs some of your original water. In BIAB its about 0.5L for every kg of grain, if you give the bag a good squeeze. so 2.5 x 0.5 = 1.25L that you need to account for.
1.75 - boil off. This is pretty variable and will depend on what pot you use, how hard you boil, how humid and or cold the weather is. BUT ... a reasonable figure to aim for and
about what you will get if you use a 20L pot for this brew - is 15% of the starting volume per hour. OR to make it easier around about 2.0L per hour. Remember - thats an estimate based on what I get for boil off in
my pot. Yours will be different. You should try a test boil in the pot you plan to use .. and substitute that figure for the one I have used. If you use your big 60L pot for a 10L batch ... you will lose a LOT more than this much, so I wouldn't use it for such a small batch.
So thats what I would start with for a 10L batch of finished beer - about 15.75L of water.
If you follow the logic I use above, you can do the calculations for any beer you brew, of any size. You just need to remember its an estimate, when you brew, try to record what actually happens with the amount of water, the amount you boil off, the volumes you leave behind ... substitute those figures in to the logic for next time... and you estimate will get better. Keep on doing it - and after a few brews, you will be able to start with just the right amount of water every time.
Thirsty