I have this problem: I'm regularly achieving 90% efficiency with my mash and sparge, and I like this effect. But I usually end up with about 30 ~ 35 liters when I aim for 20 ~ 22 liters. Boil to reduce water takes long time. So I need to reduce amount of water used without loss of sugars. How can I do it?

My current procedure, shown on most recent example:

I took 6kg of malt (weighted when dry), wet-crushed it, and mashed it in water. Total volume of malt + water was about 20 ~ 22 liters. I received about 13~15 liters of first wort at 18 °Bx. Then, before my filter bed got anything near dry, I started to pour sparge water. I ended up sparge at 2 °Bx, ending up with a total of 35 ~ 37 liters. I didn't mix it up right away, because I don't have pot large enough, so can't tell exact gravity, but at the end I got bit under 22 liters at 17.2 °Bx - perfectly consistent with BrewTarget (expectation was 22 liters at 17.1 °Bx).

Any way to recreate this result without getting to boil away 15 liters of water? Where I might went wrong?

Note - dry vs wet crushing does not change anything in that regard. Wrote it just for completness.

For sparge and filtering, I'm using this:

Photo of filtering bucket

Except now it's full metal.

  • Have you tried reducing the sparge volume, or slowing the pace of sparging, to see if you get somewhere near the expected efficiency without using this amount of water?
    – jonpd
    Oct 9, 2015 at 11:30
  • @jonpd what do mean by "reducing the sparge volume"? i can stop sparge earlier, all right, but it will mean stopping at higher gravity, thus loosing more sugars. For slower - yes, I did, but then I tend to get stuck sparge.
    – Mołot
    Oct 9, 2015 at 11:45
  • If you got the time and resources you could experiment with a false bottom. May increase your efficiency at the volume you want, although you are not likely to reach 90% Oct 16, 2015 at 12:47
  • @CleberGoncalves exensive experiments by Polish homebrewers indicate that pipe braid as filtration device is faster and more efficient. Of course name we use for it is far from proud ("sraczywężyk" - "toilet hose") but it's decent way, and I have no reason to disbelieve my pals and their results.
    – Mołot
    Oct 16, 2015 at 12:51
  • How do you remove the plastic pipe inside the metal? Oct 21, 2015 at 16:31

1 Answer 1


Your high efficiency is due to using a lot more water than you need, washing every last bit of sugar out of the mash. Ultimately, you want to collect less wort. This will result in a lower efficiency. As such, you'll need to use more grain to account for the lower efficiency.

If you had 22L at 17°Bx, then you started with 35L at 10°Bx with 90% efficiency. If you instead want ~25L (assuming about a 10% evaporation for a 60 minute boil, ymmv) at ~15°Bx, and assuming 75% efficiency, you might need to use ~30% more grain.

X units grain * 90% extraction = 10°BX * 35L , X = 388

Y units grain * 75% extraction = 15°Bx * 25L, Y = 500

500/388 = ~1.29

But your brewhouse is going to have its own particulars, so brew, measure, math and repeat.

  • Nicely worded. It follows that there must be a point at which grain:final-volume ratio is too high and its just not worth exceeding it?
    – jonpd
    Oct 9, 2015 at 14:58
  • '[A]ccept a lower efficiency'. This is really the point, to me. There are quite unalterable physical limitations on how much sugar you can extract from a particular mash bed of a particular shape, size and consistency with a given amount of water. You may get close with less, but you're unlikely to get to where you started. Oct 9, 2015 at 15:18
  • 1
    "Use less grain" - really? I mean, it'll leave me under the borders of the style sometimes.
    – Mołot
    Oct 10, 2015 at 9:38
  • 2
    You know what, you're right. If you use less water (to hit the correct pre-boil volume you need) you will have less efficiency, so you'll need to use more grain to get the correct pre-boil gravity. I'll amend my answer.
    – jsled
    Oct 10, 2015 at 16:23

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