Mash Efficiency Issues

[Markdark60]

Hey All,

I recently switched to All Grain. I have calculated my last brews efficiency to about 51% and am unsure as to why it is so low. My last brew was an IPA, I used about 13 lbs of grain. I use a 10 gallon cooler with a false bottom. I added 5.2 gallons of 163 degree water in and then stirred in the grains and got it to 150 degrees, put the top on and let it sit for an hour. I use a bucket with a spigot and a sparge arm. I got 6 gallons to 168 degrees. I vorlaufed for about 5 minutes till it was clear then started the sparge. I gathered 6.5 gallons of wort in about 40 minutes. I ended up with close to 4.5 gallons total after the boil off and trub from the hops. The OG ended up at 1.062. Not sure if extending the sparge longer would help a whole lot? I brewed a stout before this and my efficiency was about the same but I had chalked it up to not having a sparge arm and doing the sparge a bit quicker. Thanks in advance for any helpful suggestions.

 

[Natdavis777]

Seems awfully low for your setup/process. Your sparge time seems fine. Just a few questions:

1: Is your 10 gal cooler the Rubbermaid kind or is it a rectangle? If its the Rubbermaid kind with a FB, you wouldnt have much of any deadspace, thus not leaving some fermentables behind lowering the efficiency. The rectangle coolers can have deadspace issues (my first setup was this and I had to tilt the cooler during lautering to gather the wort stuck in the dead space)

2: Are you maintaining your mash temp for the entire mash process? It didnt sound like you were pre-heating your MLT, so starting off at 150 in MLT that hasnt had its thermal mass zero'd out could cause some loss in temp through the walls of the cooler, and dropping the desired mash temp down out of your desired range.

3: What does your water look like? Water greatly affects the mash pH. If the pH is off by a lot, it can impact efficiency as well. This typically isnt something new AG brewers address first, as getting the AG process down is typically more of a priority. I just wanted to address water as it could be a contributor to poor efficiency as well.

 

[doug293cz]

I've got you at about 60-61% brewhouse efficiency. The math (including an assumption of 4% moisture in the grain):

Potential points = 13 * 37 * 0.96 = 462
Fermenter points = 4.5 * 62 = 279
Efficiency = 279 / 462 = 0.604 => 60.4%​

Any idea how much volume you lost to kettle trub? With that number we could estimate your mash efficiency.

Brew on

 

[Markdark60]

The cooler is cylindrical, I haven't checked the temperature during the mash I just put the lid on and left it so that could be the issue, I also didn't know about preheating it. Does that just involve putting mash temp water in it for a while first? I have baltimore county water that I looked up on the internet, I need to get an actual report but havent done it yet, I also have a filter on my sink so not sure how much that effects it. I used EZ water calculator with the data i found on my county water and it said my estimated PH was about 5.6 during the mash. I bought 5.2 stabilizer a little while ago but read a bunch of reviews saying that it didnt work and just gave a funky taste so i decided to not use it. Do you think not preheating could cause that big of a drop in efficency?

I lost probably around a gallon to trub, I did a 50 minute hopstand with 4 oz of Azacca hops, I always lose a fair amount when I make IPA's. I tried bagging them one time based on a suggestion from my local homebrew shop and ended up with an IPA with barely any hop flavor or bitterness, I think I tied the bags too tight but havent done it since then because of it.

Thanks for the replies btw.

 

[doug293cz]

Ok, if we put your temp adjusted post-boil volume at 5.5 gal, then the math becomes:

Potential points = 13 * 37 * 0.96 = 462
Kettle points = 5.5 * 62 = 341
Mash Efficiency = 341 / 462 = 0.738 => 73.8%​

That's not a terrible mash efficiency, but nothing to write home about. And you can see how much trub loss affected your brewhouse efficiency.

Assuming you don't have channeling during sparge, your lauter efficiency should be 85-95%, which would put your conversion efficiency at 77-87%.
In a well conducted mash, conversion efficiency should be over 90%, and 98%+ is achievable. If your actual mash pH was close to your estimated pH, then that is not the source of your poor conversion efficiency. If your mash temp dropped into the low to mid 140's that could be a contributor. And as always, too course a crush is often the main contributor to low conversion efficiency. You should crush as fine as you can without getting a stuck sparge.

Brew on

 

[Markdark60]

I use the mill at my lhbs, i asked one of the people there and they said they only run it through once but maybe I need to do it twice, I assumed the cooler wouldnt lose that much heat with the insulation but I guess that could be part of the problem. Next time ill try crushing them twice and see how it does. Thanks for all the help

 

[Natdavis777]

For preheating the MLT, just heat your strike water 5-10 degrees higher than your strike temp. The temp will drop some as the walls of the cooler absorb the head and zero out. You may have to stir the water a bit to get it down to your strike temp, then dough in as normal.

 

[Markdark60]

That must be the issue because I was looking at pictures of grain crushes and I'm pretty sure mine was crushed correctly. I'll try preheating next time. I didnt realize that you could lose that much heat. Thanks again.

 

[Gavin C]

Here is a bit on calculating mash and brewhouse efficiencies. If you're concerned about dialing in your system accurate measures are the key.