Author Topic: Can't get above 50% efficiency, what's going wrong?  (Read 1822 times)

Offline PDY

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Can't get above 50% efficiency, what's going wrong?
« on: January 23, 2017, 05:19:01 PM »
Hi guys,

AG newbie here. Any help much appreciated. So far my couple of batches I haven't been able to hit more than about 2% ABV due to very low OG and terrible efficiency (I think about 50%). Details below, where do you think it's going wrong?

Details:

I'm aware this is a rather 'rustic' setup! If it's simply a case of needing better equipment then good to know:
•Heated 1 1/2 quarts of water per lb of grain to 160F in a stock pot
•Added grain and stirred, temp got down to approx. 150F
•Put stock pot in a pre-heated (and turned off) oven, and left for 60 mins, checking temp every 15 mins, I was pretty confident I stayed between 148-160 (it got a bit hot at first but I stirred until cooler)
•Poured mash into large fine mesh colander over bucket
•Then slowly poured 170f water heated in separate pans over the top, trying to cover as much of the grain as possible
•This took about 15 mins before hitting 1 1/2 gallons pre-boil volume
•Cleaned out stock-pot, added colander on top and recirculated wort through grains
•Then brought to a rolling boil and followed hop schedule
•Then cooled in 20 mins to 75F in an ice bath
•Poured through fine mesh strainer into fermenter
•Was slightly below 1 gallon (probably due to large stock pot, big surface area) so topped up with water, but not much
•Pitched yeast etc

Was aiming for OG of 1.050 (it's an APA), and I've hit 1.035... which is obviously not great. Where is the most likely misstep? I'm thinking sparging, as the water got through so quickly...




Offline dmtaylor

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Re: Can't get above 50% efficiency, what's going wrong?
« Reply #1 on: January 23, 2017, 05:33:14 PM »
Welcome to the best homebrewing forum on the interwebs!

Your process is almost identical to mine, except my batches go from about 2.5 gallons preboil to 1.7 gallons after.  One oddity in your process that I noticed:

•Then slowly poured 170f water heated in separate pans over the top, trying to cover as much of the grain as possible
•Cleaned out stock-pot, added colander on top and recirculated wort through grains

If you are sparging first and then recirculating after the sparge, then your spent grains are soaking up a lot of the good sugars!  This is out of order and hurting your efficiency significantly.  You should mash in a bag (BIAB), and recirculate first and then sparge after, more like this:

•Pull bag from kettle and set on colander over bucket
•Pour the sweet wort from the kettle through grains and colander
•Then slowly pour 170f water heated in separate pans over the top, trying to cover as much of the grain as possible

This will likely fix your issue.

Also ensure you are crushing the grains enough.  If using the mill at your LHBS, then double crush.  If using your own mill, set the mill gap to the thickness of a credit card or slightly thinner.

Hope this helps!  Let me know if you have more questions -- I might be the only other guy on the interwebs who brews like you do!   8)
Dave

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Offline PDY

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Re: Can't get above 50% efficiency, what's going wrong?
« Reply #2 on: January 23, 2017, 05:56:00 PM »
Thanks for the welcome!

Interesting... I didn't even think about the sugars in the wort being soaked back up by the grains...

Will try the BIAB method this weekend in that case. Will also give the LHBS milled grains an extra crush.

Thanks! My first batch tasted ok but at 2% abv was missing the other critical component...

Offline SilverZero

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Re: Can't get above 50% efficiency, what's going wrong?
« Reply #3 on: January 23, 2017, 08:47:29 PM »
I'm not so sure the sugars are getting trapped by the grains again, but to be safe I'd just get the first runnings off the grains and then sparge, not recirculate with the sweet wort. I'd be more inclined to think about the following (some repeats from above):

  • A proper crush will be the biggest contributor to better mash efficiency. Double crush if you're at the LHBS, or get a mill of your own and set it tight and condition your grain.
  • If you're using a bag, consider either full-volume mashing if you can, or dunk sparging by taking the bag out of the mash tun, squeezing it to get the sweet wort out, and then dunking in another pot with your heated sparge water (at like 185F) and repeating. Silicone gloves will make this easier. :) If you're still just using the colander, consider dumping the grains into the sparge kettle and stirring it up, letting it sit for a few minutes, and then stirring and straining that into the boil kettle.
  • Are you weighing your grains accurately? With smaller batch sizes, a small difference in grain weight can lead to a noticeable difference in actual gravity. The same goes for liquid volumes. Check your equipment and make sure your gallon is really a gallon, and hopefully that you can accurately measure more like down to the quart if not down to the 0.1 gallon level.

Hope that gives you some thoughts to work from!

but at 2% abv was missing the other critical component...

Haha! ;D
« Last Edit: January 23, 2017, 08:53:38 PM by SilverZero »

Offline curtdogg

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Re: Can't get above 50% efficiency, what's going wrong?
« Reply #4 on: January 23, 2017, 10:16:47 PM »
Don't forget mash pH.

Offline SilverZero

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Re: Can't get above 50% efficiency, what's going wrong?
« Reply #5 on: January 24, 2017, 12:13:18 AM »
Don't forget mash pH.

I could be mistaken, but I don't think pH has much impact on mash efficiency. You'll get better conversion efficiency for sure and better fermentability, and better beer overall. But if the OG is off by 15 points, that's a matter of starches being totally left behind, converted or not.

I absolutely agree that mash pH is quite important, and it should be something the OP looks at, but he's gotta get the starches (and enzymes) into the liquor before he worries about how well the starches are converting. In my early days I was hitting my pre- and post-boil OGs on the dot before I ever started thinking about pH.
« Last Edit: January 24, 2017, 12:16:40 AM by SilverZero »

Offline klickitat jim

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Re: Can't get above 50% efficiency, what's going wrong?
« Reply #6 on: January 24, 2017, 12:56:01 AM »
With brand new folks I often wonder about obvious stuff that might not be obvious to them, and you're always hesitant to ask for fear of sounding like a jerk. Crush wasn't mentioned by the OP, so we have to assume it was properly milled grain and not just..  grain

I don't think we know WHAT grain either

Offline Pricelessbrewing

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Re: Can't get above 50% efficiency, what's going wrong?
« Reply #7 on: January 24, 2017, 01:59:48 AM »
Need more info and measurements in order to actually analyze this. Until then, all we can do is spout possible solutions without any specifics. If you don't record first runnings gravity and volume (and adjust for temperature) then there's no way to seperate mash efficiency into the component parts (conversion and lauter).

Lauter efficiency issues

  • Batch sparging you should stir to ensure homogenous gravity throughout the sparge volume
  • Flysparging you should sparge slowly to minimize chanelling
  • Sparge ratio has a minor affect on lauterr efficiency
  • Any mashtun losses will contribute to a proportional loss in lauter efficiency

Mash efficiency = conversion * lauter, so look above for a solution.

Brewhouse = Mash efficiency * preboil volume / volume into fermenter. Any losses in the brewkettle will affect this.

Offline majorvices

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Re: Can't get above 50% efficiency, what's going wrong?
« Reply #8 on: January 24, 2017, 02:06:43 AM »
Make sure you are chilling your hydrometer reading before testing too.

Offline PDY

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Re: Can't get above 50% efficiency, what's going wrong?
« Reply #9 on: January 24, 2017, 09:44:37 AM »
Thanks for the replies all. Some more details below in case that helps!:

* The grain was crushed/milled by the LHBS, well technically ordered online from them. I don't really know what a good crush looks like, but there was a mix of cracked grains and about a 1/5 of it was flour consistency

* In terms of what grains, I was following this recipe but divided simply by 5: http://beersmithrecipes.com/viewrecipe/769261/summer-is-coming
So that's 1.411lb Pilsner (note that's not .411 oz but .411 of a pound, if that makes sense)
2.116 oz Melanoiden
1.41oz Caramalt (couldn't find Caragold, reasoned possibly wrongly that this was close)
0.214lb Honey malt (the recipe states just Honey, I assumed this wasn't actual honey, but instead honey malt)

* I didn't record SG until into fermenter (and top-up), so am judging efficiency purely on how close I got to the est. OG stated in the recipe

* The accurate weighing could be a good issue, I'm using a digital scale but it doesn't go lower than 1g (I converted the oz to grams because I'm in the UK).

* Also didn't adjust hydrometer reading, I suspect it wasn't miles off, my kitchen tends to sit at about 60f at this time of year...

Offline mainebrewer

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Re: Can't get above 50% efficiency, what's going wrong?
« Reply #10 on: January 24, 2017, 11:07:30 AM »
I noticed that you measured SG after topping up with water.
It is difficult to get wort and water to completely mix, so your hydrometer sample may have been more water than wort.
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Offline hopfenundmalz

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Re: Can't get above 50% efficiency, what's going wrong?
« Reply #11 on: January 24, 2017, 01:12:33 PM »
Don't forget mash pH.

I could be mistaken, but I don't think pH has much impact on mash efficiency. You'll get better conversion efficiency for sure and better fermentability, and better beer overall. But if the OG is off by 15 points, that's a matter of starches being totally left behind, converted or not.

I absolutely agree that mash pH is quite important, and it should be something the OP looks at, but he's gotta get the starches (and enzymes) into the liquor before he worries about how well the starches are converting. In my early days I was hitting my pre- and post-boil OGs on the dot before I ever started thinking about pH.

If the pH is above 6, the conversion suffers, and the efficiency goes down in a hurry as you go more above 6.

Saw a graph of that in a talk once. The conversion efficiency is fairly flat in the normal mash range.
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Offline SilverZero

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Re: Can't get above 50% efficiency, what's going wrong?
« Reply #12 on: January 24, 2017, 02:01:40 PM »
The recipe may have meant actual honey, as an adjunct.

 http://beersmith.com/Grains/Grains/grain_43.htm

Could be part of the problem, but if you've had poor efficiency in other batches it might not be the only issue. I'd have to plug your grain bill into a calculator, and I'm not on my computer right now.

Edit: I guess by weight it shouldn't make much difference.
« Last Edit: January 24, 2017, 02:32:23 PM by SilverZero »

Offline klickitat jim

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Re: Can't get above 50% efficiency, what's going wrong?
« Reply #13 on: January 24, 2017, 03:11:35 PM »
My bet would be stratification in the fermenter causing low gravity

Offline PDY

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Re: Can't get above 50% efficiency, what's going wrong?
« Reply #14 on: January 24, 2017, 03:27:40 PM »
The recipe may have meant actual honey, as an adjunct.

 http://beersmith.com/Grains/Grains/grain_43.htm

Could be part of the problem, but if you've had poor efficiency in other batches it might not be the only issue. I'd have to plug your grain bill into a calculator, and I'm not on my computer right now.

Edit: I guess by weight it shouldn't make much difference.

So using honey you would literally add it to the mash as if it was one of the grains?