Efficiency still in the crapper

[mr_wibble]

G'day,

Here's the on-going saga with my efficiency ~

I talked to the LHBS dude, and he advocated stirring the mash to help improve my efficiency.

So on the last brew, here's how it went:

Buy roughly 6kg of grain (60% pilsener, 40% wheat), for a 23 litres brew at 65% efficiency

• Pre-warm mash tun a bit (it was 6 degrees outside, as I started at 05:30)
• Add Grain
• Add 15 litres of water at 76C to hit step temperature of 67C
• Stir vigourously
• Wait 15 minutes
• Stir Vigourously
• (repeat 3 times)
• Draw off wort
• Add 21 litres of water at 76C
• stir vigorously
• Draw off 2nd-runnings

I estimate I had about 27 litres in the kettle

Boil vigorously for 1 hour (add hops etc.)

So ... I boiled too vigorously again ... ended up with 18 litres in the fermenter.

But since I boiled off so much I actually hit the desired specific gravity - 1.052 (that's 0.002 over).

So even with the efficiency bar set so low, I still only achieved about 78% of that... what does that make the final efficiency ... about 50% right? *sigh*

Attached is some photos of my esky-tun, obviously it has a lid too.

I tasted some grain after sparging, it was still very sweet.

Maybe I should double-sparge or something ?

Any ideas?

thanks,
-kt

 

[vortex]

What's your crush size/mill gap? How long are you taking for your sparge? Sparging too fast will leave sugar behind

 

[MikeHell]

Have you rated the extract/yeild percentage of the grain accurately in your recipe software/calculator?

Personally I do equal mash and sparge water (generally 3L water to 1kg grain), so for you would be 18L mash & 18L sparge, might be worth a go.

 

[manticle]

Before you start looking at ways to improve, find out which part of the process needs improvement. Are you not achieving proper conversion?

Measure first runnings gravity and get a sense then if that's where the problem is, look at strike temps, grain crush, measuring equipment, mash pH etc.
Are you not extracting enough sugar from your sparge? Look at manifold design and placement, sparge temperatures, sparging technique etc.
Find out where and what the problem is before throwing every tool at it trying to fix it.

In my experience you shouldn't need to stir that much to fix efficiency issues. You'll just lose temperature.
Meanwhile set your efficiency to where it actually is, rather than where you want it to be and adjust recipe accordingly till you work it out (obviously set it where you want it when running your tests to see where and how far off you are).

 

[Thefatdoghead]

Is your thermometer correct or have you checked with a glass type thermometer? Also is the wheat malted or raw or what? As Manticle said, check your PH as this may be out as well.

 

[verysupple]

What others have said is of course correct, I just want to add my experience.

I've only done 14 brews with grain (partials and AG) and when I started I would get ~65% eff. into the kettle and it slowly rose to ~75% as I improved. Then I did a couple of batches with large portions of wheat malt (>50%) and my efficiency took a big hit and dropped to ~50%. I looked at things like pH and water chem, but couldn't adjust the crush as many said to do with wheat becuase I buy my grain already crushed from the HBS.

To make a long story short, I figured out I wasn't getting very good conversion with the wheat and I just needed to mash longer. When I went from 60 min to 90 min mashes my wheats got up to my normal efficiency. This might work for you, but as Manticle said, you should figure out where your problem is, i.e. conversion, lautering etc.

Since then I've increased my usual efficiency into the kettle to 80 - 85% by doing a mash out. The higher temp (lower viscosity) lets me get a lot more liquid (and therefore sugars) out of the grain (I do maxiBIAB).

So now I'm happy with both my conversion eff. and my "lautering" eff.

EDIT clarification

 

[MikeHell]

Similar experience as above, with addition of only 12% wheat malt, brought usual 75-80% efficiency down to 65% using the same routine as usual.

 

[pyrosx]

Temperature - you've listed a whole bunch of steps, and only mentioned temperature twice - 76C for water out of a HLT.

If the thermometer in your HLT is even a couple of degree's off, and you're not measuring anywhere else.... then everything beyond that is going to be out of whack.

 

[mr_wibble]

What's your crush size/mill gap? How long are you taking for your sparge? Sparging too fast will leave sugar behind

Grain crush size is whatever the LHBS sets it to.

I guess my sparge takes about 15 minutes to run off, but I haven't timed it.

 

[mr_wibble]

Thanks for all the info ... I'll have to cogitate on all the ideas and suggestions a bit.

I don't take mash temperature measurements, I take it on faith that adding X degrees of water gives me the target temperature. Which on the face of it does sound a bit naive.

 

[manticle]

Iron out all the possibilities.

Definitely measure your mash temp accurately.

Every time.

 

[pyrosx]

http://www.wiltronics.com.au/catalogue/180803/science/thermometers

The sub-$10 one on the bottom of that list... buy 2.

Test both in heavily iced water, then in kettle-still-on-boiling water... the one that reads closest to 0 and 100 is your brewery thermometer. The other one that is only a degree or so off is great for the kitchen.

 

[pyrosx]

I'm completely serious about having a second digital thermometer for the kitchen too... if you're into beer enough to be attempting AG homebrew, i'd be stunned if you didn't have an interest in cooking decent food as well. I'd probably let someone take away my knives before letting them have my thermometer.... The difference between chicken at 65 and 75 is only about 5 or 10 minutes in the oven/bbq, but the difference in taste and therefore enjoyment is ridiculous - and there isn't another tool, method or trick in the world that will tell you properly when that chicken is done. And don't get me started on deep frying oil temperature....

 

[slcmorro]

The difference between chicken at 65 and 75 is only about 5 or 10 minutes in the oven/bbq, but the difference in taste and therefore enjoyment is ridiculous

And not throwing it up the next day

 

[vittorio]

i normally batch sparge because its much quicker but the efficiency is always low.... so i found a way around that, add 10-15% more base malt to the brew when batch sparging and it will equal to the right efficiency amount!

 

[jimmy01]

I have had similar problems when there is a high % of wheat in the grain bill. Have found running the wheat malt and raw wheat through the mill twice helps to improve efficiency

 

[BeerNess]

Grain crush size is whatever the LHBS sets it to.

I guess my sparge takes about 15 minutes to run off, but I haven't timed it.

Grain crush - Specify with your LHBS!!! Otherwise you can get into all sh!t if they just throw it through at whatever it was last set to, massive efficiency changes possible there.

Sparge - I'm a BIABer so not an authority but are you letting your batch sparge rest for 30 min or so before running it off?

Smarter people than I have already highlighted wheat being better in a longer mash.

Record your 1st and 2nd runnings gravity, get some iodine to check your conversion.

Sounds like even for a 60min boil you need to increase your mash/sparge volumes to compensated for your evaporation rate.

Something I've learnt recently that's helped me with some brewhouse problems is MEASURE AND RECORD EVERYTHING for every brew.

Good luck!!!

 

[pimpsqueak]

So are you actually doing a mash-out?
If you stirred 3 times and it was that cold outside, you must have lost a few deg.
Then you added 21L @ 76 deg which given the volume already in your tun, wouldn't have hit 75-78 deg.
These temps reduce the viscosity of your mash and make it easier to extract a higher percentage of sugars.
Next time, do a 90 min mash, perform a starch iodine test for full conversion and then give it a 10 min rest at mash out temp before running off and sparging.

My 2c.

 

[yum beer]

I agree with the idea of upping your grain bill amount.
I feel a lot of brewers get caught up too much with hitting certain eff. numbers. Yes it would be great to hit 80% every brew but the reality is we are all using different equipment to make our beer.
Keep records and work towards getting consistent figures from your brew day.
I use BIAB with a seperate dunk sparge and hit around 61-63% eff. into the fermenter....not great but thats what my sytem gives me and it works nicely for me, I need an extra .5 - 1kg of grain to get my volumes than I would if hitting 70% or better, but at under $3 extra for each batch I don't care.
I'm half way through fitting out my esky mash-tun and no doubt will have to start again regards hitting the numbers I want.
The most important thing is getting your volumes into the fermenter right; at the SG your after.

 

[verysupple]

I agree with the idea of upping your grain bill amount.
I feel a lot of brewers get caught up too much with hitting certain eff. numbers. Yes it would be great to hit 80% every brew but the reality is we are all using different equipment to make our beer.

Some of us need to keep the efficiency up because we can't mash any more grain . I use a BigW 19 L pot and with 4.5 kg of grain and a liquor-to-grist ratio of 2.67 :1 (L/kg) it's full to the brim.

Sparge - I'm a BIABer so not an authority but are you letting your batch sparge rest for 30 min or so before running it off?

I'm not an authority either, but I've found that if you get all the conversion done in the mash you don't need to let it sit, just give it a really good mix to get the sugar into the water and it's all good. If you get poor conversion during the mash and then let it sit for 30 min at ~76 C isn't that going to make a rather dextrinous beer? I know a-amylase will probably denature at that temp but it's going to take a fair while, and before it does it's going to go nuts on the starches, but b-amylase will have denatured and you're left with dextrins etc. Although I could be wrong.