Author Topic: Efficiency major issues  (Read 3893 times)


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Efficiency major issues
« on: May 19, 2007, 01:42:11 AM »
Hi all, first post here, so please be gentle!

I have been grain brewing for a while now, but since I have got my new mash tun, I have experienced really bad efficiency.
The last 4 brews have all been under 60% efficiency.

Here's today's brew
Today's brew:

8kg grain, crushed this morning (fine crush if anything, not coarse)

Mashed with 22L of pre-boiled water, well mixed to hit 70deg C in 66L rectangular esky (cooler)
Held for 1 hour (lost 5 degrees)
Batch sparged with 34L to achieve 42L preboil volume

I use braid (until the false bottom arrives next week!), and there is about 2L of dead space and uncollected (but fully mixed) runnings.

Pre boil gravity of 1047 would have worked out at 80% efficiency

I got a pre boil (after cooling) gravity of 1032 or 54.7% efficiency

Bottom line is 8kg of grain for a preboil SG of 1032

I'll happily live with anything above 70% efficiency, but 55% is rank.

What am I doing wrong? Any ideas?

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Re: Efficiency major issues
« Reply #1 on: May 19, 2007, 06:31:11 PM »
Efficiency troubleshooting 101:
Crush - is it well-crushed without disintegrating the hulls? Can it be crushed more? (sounds like not the issue here)
Mash pH - are you using all light grains? Do you have the same issue with darker worts (e,g., a stout) where the pH is lower? Try an acid rest or a bit of acidulated malt (~5-10% of grain bill) and see if that changes anything.
Sparge - are you sparging only once? Try sparging in volumes roughly equal to your first runnings, and check your SG in the mash tun after you're done lautering. Also, do what you must to get your mash up to 75° before running off. Options include hot liquor infusion or thin decoction, boiling a third of your runnings or so and reintroducing them.
Mash temp - is your mash too hot or cold? 70°C is a bit high, but should fully convert if given time. Try mashing for 75 minutes next time, or get some iodine and do a conversion test before mashing out.

The deadspace shouldn't be much of an issue, since you're really only losing the volume from the last sparge, hopefully low-SG.
Hope this helps, and good luck. You're right; you should be able to get better than that.


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Re: Efficiency major issues
« Reply #2 on: May 21, 2007, 01:28:34 AM »
Well crushed, mashph fine, although I will change sparging technique.
My thermometer apperas to be the culprit, seeing me mash at what I thought was 70, but ended up being 73...therefore enzymes stopped in their tracks!