For my first all grain brew I bought an octoberfest all grain kit from morebeer. Before brewing with it, however, I decided to try a very cheap smash recipe. I ended up with a very low efficiency (about 65 percent), and threw in some DME I had on hand to try and raise my gravity by a few points.

I'd like to brew again in the coming weekend, and while I've made notes on how I can increase my efficiency, I'd like to have a backup plan to turn it into a partial mash if need be.

When correcting for a poor mash, how do you decide what grade of DME to get? I'm assuming its based of SRM, so an SRM of 10 would probably mean an amber DME. Im also assuming I should introduce it right after I've collected and measure my wort?

  • 2
    i think a fail safe is going too far, but if you want help to increase your efficiency, i'd suggest you offer a lot more information than this. Tell us the equipment you're using and your process for a start - then any specific issues you think might be a problem, such as too much dead space in your mash tun (so not collecting all the wort), collecting more wort than necessary (over-sparging), etc etc.
    – dax
    Oct 15, 2013 at 9:36
  • I think next time I am going to keep even more detailed notes than I did during my first attempt. Like Ive written in other comments, there were some things that I identified immediately after I completed my brew. However, my main question wasnt about fixing my mash, but rather, if there was something I could do when things go wrong. That said, it seems like everyone is suggesting I compensate for my efficiency (whatever it may be) beforehand.
    – kenyabob
    Oct 16, 2013 at 17:07
  • compensating for efficiency beforehand is the thing to do - often this is tied to equipment and there's probably little you can do to improve that overnight. but keeping detailed notes will improve your brewing far more than spending a bunch of money on the 'best' equipment anyway. good luck!
    – dax
    Oct 16, 2013 at 17:11

3 Answers 3


65% is not bad. Most recipes only expect 70%, so you're not going to be that far off to begin with if you are getting 65%. I wouldn't do partial mash unless you want to. Use Beer Smith or BrewTarget and just adjust your recipe for your efficiency. Read up on how to calculate efficiency first. Understanding your volumes and gravities at each step will help you improve. If you really want to adjust your gravity, 1 lb of DME will add 9 gravity points to a 5 gallon batch. I would just use pale DME; it's not going to affect it much, but if you use amber or dark it may.

EDIT: I should add.. the simple technique of adding grains to water (instead of water to grains) will make it easier to avoid clumps and dry spots. Stir the crap out of your sparge as well as your mash, and vorlauf both the mash and the sparge. Those techniques added about 2-3% each to my efficiency, and I'm getting somewhere around 75-80 pretty consistently with a very rudimentary batch sparge setup. I use brewtarget and pretty consistent with volumes and efficiency, with the caveat; lower water to grain ratios and higher gravity beers reduce efficiency and vice versa.

Also, lower water to grain ratio will hurt your efficiency, but may be required for style (mouthfeel and maltiness), so better to anticipate a bit lower efficiency in that case and adjust accordingly, rather than sacrifice style for efficiency. Higher ratios, like 1.5 will improve efficiency, but will make for thinner beer.

  • Encouraging words! Luckily, I've identified a few things I could do better, mainly agitate the grain when I do my batch sparge, try and do two smaller batch sparges as opposed to one big one, not OVER sparge, and also try and ph stabilize the mash. Those, at least, have been some problems I recognized from my previous attempt.
    – kenyabob
    Oct 16, 2013 at 16:06
  • 2 batch sparges will increase your efficiency so little that it's not worth the effort.
    – Denny Conn
    Oct 24, 2013 at 16:15

Don't worry too much about increasing your efficiency. The important thing is is have an accurate measure of it. Your first mash showed an efficiency of 65%, so go with that until you've done more brews and narrowed it down. I don't know much about all grain kits, but they must make some assumption about efficiency and include the corresponding amount of grain. What you need to do is add enough base grain (pale, pilsner, or 2-row, depending on the style) to bring the gravity up to the target.

Brewing software can really help with this. You enter the amount of each grain and your measured efficiency, and the software will estimate he starting gravity. If the estimate is low, add base malt until it reaches the target.

  • 2
    +1 for knowing your efficiency. This is key. Your desired fail-safe is knowing your efficiency and preparing for it ahead of time.
    – Scott
    Oct 16, 2013 at 2:49
  • I did ten pounds of vienna just so I could easily calculate my efficiency. Like others have told me when I asked what the easiest way to adjust for poor efficiency, their response has been "Buy more grain!"
    – kenyabob
    Oct 16, 2013 at 16:10
  • Depending on your equipment setup, there are other things that can come into play (as you've noted above). As an example, I do BIAB, and I think it helps to really, really drain the grain bag completely to get as much first run wort out as I can.
    – object88
    Oct 16, 2013 at 16:48

99% of the time, efficiency is tied to the quality of the crush. Unless you crush the grain yourself, you have no control over it.

  • While this may be true and useful, the question is focused more on how to correct wort from a low efficiency mash, not how to prevent a low efficiency mash.
    – fire.eagle
    Oct 24, 2013 at 19:05

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