Can i brew an AG recipe in 2 to 3 stages?

[Dazzelknight]

Rinse these with chemsan, pour in ur wort, squeeze out the air and stick the lid on,, u can leave them as long as you want before sticking into ur fermenter

 

[peebee]

Rinse these with chemsan, pour in ur wort, squeeze out the air and stick the lid on,, u can leave them as long as you want before sticking into ur fermenter

I'm surprised the "no chill" bunch haven't chipped in. But that post by @Dazzelknight it pretty close.

 

[kenstel]

I'm guessing you're BIAB. Providing you can get all the grain for your 20 litre brew in your 10 litre mash tun, as @Jim Brewster suggests, I'd mash the whole lot in as much water as you can fit in. After an hour drain the wort and do a second mash with fresh water. If you can recirculate the mash all to the good. After about 30 minutes drain the second wort and repeat until you have sufficient wort for your boil. This is the method I use routinely but my mash tun will accommodate 3 gallons (15 litres) of strike water for the mash.

If the first mash is 60 minutes, why is the 2nd only 30 minutes? Obviously the grain will be partly depleted after the first mash, but how did you arrive at 30 minutes for subsequent mashes? Experience? Advice elsewhere? It's an interesting technique, I'm just interested in how the dynamics work out. I asked a vaguely similar question elsewhere. My question was about making a more concentrated brew and then topping up with wasted in the fermenter.

My thoughts are that if the brew is too concentrated, ie too much grain/insufficient water the wort will be too concentrated to allow sugars to be extracted from the grain. A second mash will allow the extraction to continue, but the question is how much water/how much time. Not enough of either will not extract everything, too much may cause something undesirable (I don't know what), lead to a wort that is too weak, or simply waste time.

 

[Buffers brewery]

If the first mash is 60 minutes, why is the 2nd only 30 minutes? Obviously the grain will be partly depleted after the first mash, but how did you arrive at 30 minutes for subsequent mashes? Experience? Advice elsewhere? It's an interesting technique, I'm just interested in how the dynamics work out. I asked a vaguely similar question elsewhere. My question was about making a more concentrated brew and then topping up with wasted in the fermenter.

My thoughts are that if the brew is too concentrated, ie too much grain/insufficient water the wort will be too concentrated to allow sugars to be extracted from the grain. A second mash will allow the extraction to continue, but the question is how much water/how much time. Not enough of either will not extract everything, too much may cause something undesirable (I don't know what), lead to a wort that is too weak, or simply waste time.

The 60 minute mash is when the starch turns to sugar. As I understand it the conversion process requires the grain to be kept at mash temperature for 60 minutes to achieve complete conversion. This can happen with a thick or watery mash. I think I’ve read that the thicker the mash the more efficient but might’ve got that wrong. After that it’s a matter of “rinsing” as much of the sugars from the grain. The 30 minutes was an arbitrary number I came up with for my process and I give everything a stir half way through. But I check the gravity of the circulating wort with a refractometer and that shows the gravity rising steadily through the 30 minutes then levelling off when I drain the wort off and repeat for a second time. The wort from the last 30 minutes tends to be low gravity indicating the majority of sugar has been removed. In my process for a 4-5kg grain bill I mash with 3 gallons of water initially and produce around 2 gallons of wort. The second and third mashes I use 2 gallons of water yielding a total of 6 gallons of wort.

 

[kenstel]

Yes, obviously there is a law of diminishing returns. You could repeat the mash 10 times, but if each wort is getting weaker, then the whole wort is getting weaker and you'd probably be better off with less wort but more concentrated, after all, not many people want to make 60 pints of 2%ABV beer.

I was just wondering how you came up with your times, but you've done some measuring so there is some logic to it. I might try an experiment like that (some day). It might be a good learning experience.

 

[jof]

It's like batch sparging.
Not necessarily an "approved" method, but if it works for you and you get good results then no reason not to share the technique.