Drop In Efficiency

[MarkA]

My last few batches have seen a drop in efficiency from 72% to 67% (worked out in Beersmith)

My process, equipment including hydrometer, sparge rate and water are the same.

In December I made a bitter;
Efficiency set at 72%
Estimated pre-boil gravity - 1.046
Measured pre-boil gravity - 1.048

My last batches have been lower;
Old Fart Clone
Estimated pre-boil gravity - 1.058
Measured pre-boil gravity - 1.052

Kveik Bitter
Estimated pre-boil gravity - 1.052
Measured pre-boil gravity - 1.043

I've had to re-adjust efficiency to 67% in Beersmith to get the numbers closer.

The only variable I can think of is that the latter brews were a new batch of crushed malt from the Malt Miller, has anyone else noticed any difference?

Any other suggestions/solutions welcome!

[Eric]

Although possible, it is unlikely that crushing done by the Malt Miller would be the cause. Frequent handling of a large batch will enable grains to settle, with the top having fewer vital components. If this is so, you should find your efficiency to rise as those at the bottom come within reach.

High extraction efficiency is generally a result of steady and prolonged sparging, but with today's range of single pot systems, it is often sacrificed for a quick and easy brew day.

[MarkA]

Although possible, it is unlikely that crushing done by the Malt Miller would be the cause. Frequent handling of a large batch will enable grains to settle, with the top having fewer vital components. If this is so, you should find your efficiency to rise as those at the bottom come within reach.

High extraction efficiency is generally a result of steady and prolonged sparging, but with today's range of single pot systems, it is often sacrificed for a quick and easy brew day.

Thanks Eric. The MM crush hasn't been an issue in the 10+ years I've been using them so unlikely to be that, like you say.

The last few batches have had a slow sparge, an hour and a half to get 24ish litres, on a 3V system, just to see if it made a difference.

[Eric]

Well, an hour and a half sparging should give substantially higher efficiency than you report. I can only suggest monitoring the rate of extraction with regular refractometer readings to verify there is nothing untoward happening. I'd ask Rob if he has had any complaints by others.

[IPA]

Although possible, it is unlikely that crushing done by the Malt Miller would be the cause. Frequent handling of a large batch will enable grains to settle, with the top having fewer vital components. If this is so, you should find your efficiency to rise as those at the bottom come within reach.

High extraction efficiency is generally a result of steady and prolonged sparging, but with today's range of single pot systems, it is often sacrificed for a quick and easy brew day.

Crushed malt is not available here. So I know that when weighing the malt I get the exact weight and not a surplus of chaff that has risen to the top during transport/movement.
That said with the BM including a sparge with 20% by volume of the original mash liquor I get a mash efficiency of 83%

[Eric]

After many years of buying crushed malt, to avoid this problem and have longer shelf life, For some years I have crushed my own to know in advance what extract should be achieved in advance, and while m 3V system will achieve over 90% extraction, it extends brewing time significantly more than a 20% sparge volume in a BM.

[borischarlton]

@Mark, can you drop an email to the hello@ address with what malt you are using please.

[MarkA]

Will do!