Brew Dudes

Homebrewing blog and resource

Improving Mash Efficiency

“I get 80% efficiency in my system, how about you????”

Don’t be discouraged if your efficiency doesn’t measure up with the next guy… it’s how you use it that matters.  The most important thing about starting out in all-grain is that you are getting consistent efficiency.  That is the only way to at least be able to reliably test your recipes and process.  You should be concerned about initial efficiency if it’s below say….65%.  I would consider less than that poor efficiency.  Getting 80% or greater is amazing efficiency, and I would say 75% is acceptable average efficiency.  75% is where most brewers should be shooting for (although more is better).

Here is a short list of things to consider when trying to improve poor efficiency.

1.  Check your crush!  This is the most popular item to investigate when concerned about poor efficiency, with good reason.  If your crush doesn’t expose enough actual grain kernels to the water in the mash, then you’ll never get the sugar in them into the wort.  Your crush should expose all the internal kernels.  You should have lots of little barley bits in the crush.  Having 5-10% “flour” is OK.  Be sure that in your effort to improve crush that you still see a lot of husk material.  The husk shouldn’t be getting pulverized into powder.
But as the first order of attacking poor efficiency the mantra goes….“Crush till your scared!”  It’d be better to get 90% efficiency and a really astringent beer in one batch and make corrections than spending several batches slowly inching up the crush scale.

2.  If you are a fly sparger…slow down the sparge.  Your sparge should easily take 45-60 minutes to complete.  Play with your in and out valve with just water until it takes 60 minutes to drain your HLT through your tun and into the kettle (simulated mash).  Check the flow rate buy counting how long it takes to fill a pint glass with water.  Then you can use that as a measure every-time.  If you know it takes 44 seconds to fill the glass, next time you sparge set the valves to be 44 seconds then you’ll know you have the valves set to the optimum flow rate.

3. Mash out temps improve viscosity.  This seems to help on my system, but maybe it’s not critical for everyone.  If I get my wort up to 168°F before I sparge, I tend to get a 2-5 point increase in my efficiency.  Getting to mash out is sometimes seems to loosen the flow of the sugars out of the wort.  If all else fails, try increasing the temp to mash out before running off.

There are a handful of other tricks too, but chime in if you have something to add.



Liberty Hops


When to Start All-Grain Brewing


  1. Chris

    I’ve noticed that my efficiency has gone up since I started recirculating longer and using this plus a pump:
    I used to pump through a hose and spread it around on top of the grain bed by hand, but I think I’m getting less channeling this way. I’ve seen 80%+ since I started doing the hands-off approach.

  2. wayno

    Great article! A lot of people talk about efficiency, especially when lower than expected. There’s not a lot of discussion about how to correct it. I think you covered it a short time ago. The bottom line: boil till you have the number you are looking for. The amount of wort that goes into the fermenter is secondary to the Pre-boil Gravity and efficiency.

  3. Ted

    I haven’t fly sparged in a very long time. When batch sparging, I do a mash out addition to the first batch. I have recorded the efficiency goes down as the gravity goes up because more grain is used for the same volume. In this case, the 2nd sparge water volume is less, and results in less water for the remaining sugar to dissolve in or be carried away by. With gravities around 1.050 and down, I’ve seen the efficiency rise to 80% on occasion.

    I think I’ll give the old fly sparge method another try. It will be fun to switch things up. Also, I may look into the setting on my mill.

    Also, when calculating efficiency, make sure you are precise about your volume measurements. Guessing or rounding simply wont give you a reliable result. If the post-boil volume is off by one tenth of a gallon, it will cause your efficiency to be off by 1.2%. Having an accurate dip stick is important, and using it the same way (middle of high and low points around kettle) is key.

    If your hydrometer is off by .001, the efficiency will also be off by 1.1%. If your volume and hydrometer are off, what is your efficiency???

    I like the idea of boiling to the point where the target OG is hit. The volume will probably be fairly close, but could be off by more than a quarter gallon. I’ve also found it difficult to take samples, cool and check gravity, and maintain correct hop late hop additions. For the most part, I make sure to boil a little longer than shorter. If your system is pretty much dialed in, then hitting the correct hop additions is much more important, because the gravity will only be off by a few points.

  4. john

    I find it interesting that Ted says that batches of 1.050 SG the batch sparging gives a higher efficiency 80%. It makes since. I usually make high gravity beers an have less efficient sparges using the batch method. Now I know why.
    However I do not agree with the method of boiling down to achieve the desired gravity. This is a waist of time and fuel. I prefer the addition of dry malt method. I have a reverse chiller so I can take samples during the boil and make adjustments accordingly. My numbers are perfect every time and my volume dose not change either. I made a work sheet for the calculations. It really works.
    Another item to check is the thermometer. As a lab tech I learned that dial type are fast but can be off . I found mine off by ten degrees. sparging at 158 dose not work well. Good ones have a nut on back of the dial for adjustments. I don’t know about the electronic ones. I use a mercury type to calibrate before I start brewing.

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