From what I've read it seems you Have to boil the full wort amount when going all grain. I just want to make sure that is the case, as I couldn't understand why you couldn't just boil the malt etc and make a strong wort and then just dilute it later, kind of like a beer kit? As after all the beer kit makers do sort of the same thing, the wort is concentrated and then later diluted. I'm mostly just looking to save money, but it would be fun to try out all grain. My biggest pot is around 12L and I'd be looking to do around 23L batches. thank you

3 Answers 3


No, you don't have to boil the full volume in AG brewing. I only had a 7 gal. pot when I started AG so I's boil about 5 gal. down to 3.5-4, then add top off water. Boiling less will reduce your efficieny because you don't collect as much wort. You need to use more grain to make a higher gravity wort at less volume, so you can top off afterward. That was my main motivation to get a bigger kettle and do full volume boils. But I won some awards with partial boils, so if that's all you can do you can still make great beer.

  • thank you, that is very helpful I will have to think about it all, I totally forgot that some people boil in a food grade plastic fermenter type bucket, this seems like it could be a possibility (if im fully convinced its safe) Commented Jul 21, 2012 at 11:50
  • They BOIL in a plastic bucket? How does that work? Some kind of heating element suspended in the center?
    – TMN
    Commented Jul 23, 2012 at 17:07
  • Yep. Not uncommon in the early homebrew days in the US. Still not uncommon in other countries.
    – Denny Conn
    Commented Jul 23, 2012 at 21:50

A full wort boil is not absolutely necessary, but you shouldn't be topping off too much of your volume. Your efficiency will suffer greatly from topping off. Even if you're able to hit 80% effiency with 11.5L of wort (a big if), after boiling and topping off to 23L you'll end up with below 40% brewhouse effiency. You would also definitely be limited in terms of how many pounds of grains you could work with.

This isn't an issue with extract brewing, because you get the same amount of sugars from the extract no matter how much water you use. This is not the case with grains at all, since you'll need more mash water, more sparge water, and you definitely need to boil all the wort you obtain.

Some ideas to try out all grain with your current setup:

  • Try partial mash, adding only a couple of pounds of extract. You can learn the ins and outs of all grain brewing without much of the hassle. You'll get to mash grains and save some money.The best guide I've seen for this is DeathBrewer's, and my homebrewing process is based on his.
  • Try a smaller batch size with a nearly full boil. Scaling recipes is incredibly easy. For example, you can take a recipe for 23L and make it into a recipe for 11.5L by simply cutting all the ingredient amounts in half. I scaled back my batch sizes to 4 gallons for reasons similar to yours.
  • Try splitting your batch into two simultaneous boils. If you're set on a 23L batch, you can go through your boil in two pots, adding equal amounts of hops and combining them later.
  • 1
    +1 Some great suggestions here, particularly PM and splitting the batch into two boils. A downside with two boils is that it takes twice as long.
    – mdma
    Commented Jul 20, 2012 at 16:41
  • 1
    He said 2 simultaneous boils, so no time penalty. But you need twice as much equipment. IMO, don't even worry about how high your efficiency is....it's a hobby, just do it and make beer!
    – Denny Conn
    Commented Jul 20, 2012 at 16:49
  • @DennyConn: I really only bring up efficiency for cost reasons (OP said he's looking to save money). I am totally behind don't worry about efficiency.
    – KISS Brew
    Commented Jul 20, 2012 at 16:56
  • Just going AG will save him money over extract. I think I figure that for me the lost efficiency meant I had to spend about a dollar more per batch in grain cost. Still cheaper than extract.
    – Denny Conn
    Commented Jul 20, 2012 at 17:41
  • I know the answer mentioned simultaneous, but the OP mentioned he has only one 12l kettle, so I don't see how he can do a simultaneous boil.
    – mdma
    Commented Jul 20, 2012 at 17:54

Good answers already given, although if you choose to boil a higher gravity then add top up water, keep in mind that that boiling a higher gravity wort reduces hop utilization, so you need to use more hops to achieve the same level of bitterness. (Doesn't apply to flavor and aroma hops.)

Typically it's between 10% and 30% more. The table here lists hop utilization factors by time and gravity. If you're not using brewing software, which can do this calculation for you, you can work out how much more hops to use with the formula:

Utilization at Original Gravity
------------------------------- - 1 * 100 %
  Utilization at High Gravity

For example, if your original recipe has 60min hops for a 1.050 wort, but you do a concentrated boil, with a 1.080 wort, then the amount of additional hops is:

 = (0.231 / 0.176 - 1) * 100 
 = (1.3125 - 1) * 100
 = 0.3125 * 100
 = 31.25 %

So, you'd need about 30% more hops than in the original recipe if you boil 1.080 wort rather than 1.050.

  • Good point. Negligible cost, though.
    – Denny Conn
    Commented Jul 20, 2012 at 17:41
  • 1
    Thanks, it's not the cost I'm concerned about but getting the bitterness balance. Although in fact for me it's not negligible cost - for some recipes hops are easily my biggest expense. I know they're relatively inexpensive in the US, but here I can pay 60-80kr, about $12-16 for 4 oz depending upon variety.
    – mdma
    Commented Jul 20, 2012 at 17:57
  • Thank you for the formula I'll note it down for the future it helps a lot. As I mentioned to the other posters I forgot that some people boil in food grade buckets - this seems like a possibility (if im fully convinced its safe). Commented Jul 21, 2012 at 11:51

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