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Low mash eff. And low OG

I use denny’s rectangular cooler design. I brewed an ipa today.

11.5 2 row
.5 carapils
1 C30
Doughed in with 4 gal at 169 hitting a mash temp of 152. Collected 6.5gal with a pre boil grav of 1.048 using a refractometer. Brewers friend says I got 66.6 efficiency. Why so low? Then my OG was only 1.054. I don’t get what I’m doing wrong.

Who crushed the grain? What do you do for water? How long did you mash? Explain your sparge process.

yes, yer efficiency is the culprit as to why its low, Loopie has the questions asked that need the first look… Sneezles61

Also was the mash stirred up enough to break up dough balls? Don’t worry though, you will dial it in with some trial and error.

That’s not super low, in my experience. I consistently get 65-68%. I’m not even mad, though, because it is consistent. I just plan for it and buy extra grain. You can try a finer crush, and also look for dead space in your cooler. I tried crushing finer, but had sparging problems (poor runoff) that were just as bad, so dialed my crush back again.

I buy spring water by the gallon. Arrowhead. I did a 60 minute mash and batch sparged. I tilt my mlt to get every possible Oz of wort out during the sparge and mash. I get my grain milled st my LHBS.

Low efficiency is most often caused by a poor crush. The next culprit is sparge/lautering process. I fly over batch sparge so I’ll let others tackle this. If your pH is off (ideal is 5.2-5.5) then conversion suffers.
Hint: start with your crush

I’ve heard that’s about the efficiency that some kits are based on. There are ways get more out of your grain but the important thing is being able to predict what you get consistently.

How do you start yer mash? When I did mash, 180* water, and used 1-1/2 quarts per pound. Added the malt at 4 different intervals so I could stir and be sure dough balls were broken up, then vorlauf a couple gallons to set the grain bed and monitor temp. Sneezles61

I use Denny’s cooler batch sparge method myself and have for the past 2 years. I typically hover around 75% efficiency within a point or two where I have my mill set at. I brewed up a batch of Denny’s Wry Smile from our hosts a few weeks back but my mill was having issues that day. I only managed 60% efficiency in the exact same setup that I normally get 75% on. After brewday, I took my mill apart and reconfigured it properly again. This past weekend I was right back at 78% again. Crush has a lot to do with it.


I usually get my strike water up to 169 or so and fill the cooler. I let it rest fir 10min or so to pre heat the insulation. If I have help, I have someone pour the grain while I paddle it in. This time I was alone amd did it myself. Give it a good stir and let it sit for an hour undisturbed.

Stirring is important. Once I started using the drill and paint stirrer I started seeing better efficiency.

Hey, what a coincidence…I use Denny’s system, too! :wink: #1 cause of low efficiency is crush…crush til you’re scared! Next is mash ratio…my efficiency went up when I went from 1.25 to 1.65-75 qt./lb. Next is stirring…stir thoroughly but not violently for both mash and sparge. pH and mineral content will make a bit of difference, but they have to be WAY off to have much effect.

You do??? Hahaha! Well, I think it’s time to finally buy a mill. Thanks for the help everyone.

Can you dislike a post? :yum:

No you can’t dislike a post. You could flag it for moderators attention. Unless it was flagged for being a great post, the flag would be dismissed.

Maybe a -1.060? :wink:

@denny, sorry after reading HomeBrew All-stars I’ve come to the realization that I’m a “traditionalist”. I just can’t seem to pull the trigger and try a batch sparge. I know… I know…

Why not just try it? What do you have to lose?

Money on a braid and my sanity. My whole system is set up for fly sparging. But I promise to look at your site and maybe I’ll try it…

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