Crush size and Efficiency

[Hoppy Mad]

Greetings yalll.

Last sunday I brewed a Helles Bock from BCS and my efficiency was 59%.
I dumped in alot of DME to make the preboil gravity and it is fermenting as I type.

I am really bummed about the efficiency. I thought I had my procedure down.

A mate suggested it could be the crush on the malt. Funny how he suggested it as
he crushed the malt on his new mill.

Could the crush account for about 10% drop in efficiency?

Some info on the mill.
1st time using the new mill and the grain from the mill.
The mill gap/setting was decided by putting a CD in the gap.

Cheers
Brendan

If this is correct then I will run part of the grist through the mill again with a
finer setting.

[bcmaui]

I get about 75-80% efficiency from my mill on it's default setting.

I am by no means an expert - a newbie all grain brewer (8 batches so far) that has listened to the show for a couple of years.

What does the crushed grain look like - you have various sizes of kernels in the crush with full husks?

You certain on your liquid volume calcs - i.e. is your preboil volume 30 liters instead of 25?

You batch sparge? If you fly sparge are using a false bottom - channeling could lower your eff%.

You mashed long enough and at the correct temp and mixed everything up well?

How long did you take to sparge? If you go too fast you can lose sugar potential as well.

I take about 25-30 minutes to run off 6 gallons / 24 liters.

[thatguy314]

my barley crusher is set at 1mm. CDs can be as wide as 1.5mm. You may want to tighten your gap.

Maui's crush is fairly thorough. Mine is a bit less than that.

Here's a good page on malt crush http://www.braukaiser.com/wiki/index.php/CrushEval

Look through Kai's whole page on mash / lauter efficiency. He looks at a lot of aspects of mashing.

[brewinhard]

Crush size can definitely effect your efficiency. Go buy some "feeler" gauges and start your mill gap at .040 or so. I believe mine is dialed in at @ .039 or as close to that as I can tell. The only problem is if you crush too fine, you may end up with great efficiency, but could get astringency from rinsing tannins out of your grains, or stuck sparges. Try slowing down your sparging/lautering and keep your sparge water no higher than 170 or so. Brew again and keep honing your technique!

Cheers -

Brewinhard

[thatguy314]

Crush size can definitely effect your efficiency. Go buy some "feeler" gauges and start your mill gap at .040 or so. I believe mine is dialed in at @ .039 or as close to that as I can tell. The only problem is if you crush too fine, you may end up with great efficiency, but could get astringency from rinsing tannins out of your grains, or stuck sparges. Try slowing down your sparging/lautering and keep your sparge water no higher than 170 or so. Brew again and keep honing your technique!

Cheers -

Brewinhard

He's speaking inches. 0.040/0.039" is about 1mm

[Bugeater]

As mentioned, theoretically, the finer the crush the higher the efficiency. In this scenario, the limiting factor is how fine you can get it without getting a stuck sparge from all the glue you just made.

Astringency, is the actual, limiting factor. You need to look at how the hulls look in your milled grain. The hulls in BC's photo are ideal, he could perhaps mill even a little finer, but with the efficiency he is getting, I would leave it alone. The particular mill you have, how fast you run the mill, and the moisture level of the malt, will all affect how torn up the hulls get. My mill (a single roller PhilMill) will crush much finer than BC's but my hulls look the same as his. I get 80-85% efficiency with normal gravity beers. At the other end, a Corona type mill needs to be set to a much coarser grind to get the same results with the hulls.

Basically you need to go by what the malt looks like, not by what the mill setting is. Remember, different malts vary both in kernel size and hardness. You will need to adjust the gap accordingly. Just run a few cups of your base malt through the mill and check, if it looks good, keep the gap there. When you mill the other grains, examine the grain size compared to the base grain. You can pretty much eyeball the difference and guess whatever gap change you need to make without wasting much, if any, grain.

Wayne

[Hoppy Mad]

[quote="bcmaui"]I get about 75-80% efficiency from my mill on it's default setting.

I am by no means an expert - a newbie all grain brewer (8 batches so far) that has listened to the show for a couple of years.

What does the crushed grain look like - you have various sizes of kernels in the crush with full husks?

You certain on your liquid volume calcs - i.e. is your preboil volume 30 liters instead of 25?

You batch sparge? If you fly sparge are using a false bottom - channeling could lower your eff%.

You mashed long enough and at the correct temp and mixed everything up well?

How long did you take to sparge? If you go too fast you can lose sugar potential as well.

I take about 25-30 minutes to run off 6 gallons / 24 liters.

quote]

BC and all who replied,

Thanks for looking at the thread. Some more info that could help.

I batch sparge and my volumes were correct. I had 31L preboil
When we first checked the mill we compoared the crush with that from the LHBS
which I have had 70%+ efficiency.
I mashed for 60 mins at 69c as per BCS
The mill is a 2 roller monster mill.

I will compare the crush again with a sample form the LHBS and see how I go.

[Thirsty Boy]

You can dilute the importance of the crush by giving your mash a couple of stirs and a little longer to mash. Really... crush doesn't make a squirt of difference to the potential efficiency... it makes a difference to how fast you will convert and how effective your sparge can be for a given run-off speed.

if you are batch sparging - a good stir at mash in, a good stir at 20mins, 40mins - stir in some water for mashout (if you are doing one) - stir well after any addition of sparge water. That will make sure that you are accessing all the starch, distributing the enzymes evenly along with dispersing their products, and mixing all the sugars into your sparge water.

As the ultimate demonstration of this... I have brewed and gotten 70% efficiency into the kettle, without crushing the grain at all, just to prove I could. Its just that in order to do it I had to mash for 12hrs and sparge in 2 batches that both had a "rest" of 12hrs.

The point is - that with enough time and a bit of stirring to help things along - the water will get into the grain, it will convert and you will be able to rinse out the sugars, no matter what your crush is like. So there are a few options for you to take if you happen to find that a finer crush is unworkable for you.

crush a bit finer first though

TB