I sometimes hear when people get into all-grain brewing that they are not getting close to their expected original gravity. You know that you are doing the all-grain process correctly, you are hitting your temperature as well as going by the books, yet you still are coming up with a lower gravity. I know it can get frustrating – but if you fall into this category, don’t get frustrated and in the words of Charlie Papazian, “Have a homebrew.”.
It use to happen to me when I first started getting into all-grain brewing, and these were some small adjustments that I made that really made some huge changes in my results. Anyone who brews all-grain can use these to improve their efficiency for all-grain.
The 3 Ways To Improve Your Efficiency
90 min mash
If you are currently just doing a 60 min mash, stepping it up to 90 min mash might help with getting a better conversion. Just with a simple change of 30 min you might start to see your gravity creep up closer to the expected gravity. It just allows more time for you to get all the sugars converted. 
3 Runnings instead of 2
Normally with all-grain brewing (specifically batch sparging) you end up taking your first running, and then you’ll sparge once to get your second running. If you are not getting close to your original gravity split your sparge water into half and make a third running. By doing this sometimes you can rinse more sugars off of the grains. I personally like this one a lot because it won’t take too much time and the results are pretty immediate.
Use more grains
Using more grains may also be another way to increase the gravity in your all-grain. To me it’s understanding the limitations of your equipment and brewing knowledge. While this really doesn’t help with your efficiency, it will however get you the numbers that you should be getting. If you were going to go down this road, just add an additional 15%-20% of base malt and there you go.
Conclusion
Personally if you are constantly hitting lower numbers for your original gravity, I would start off by doing all of the above. If you are still hitting low numbers, then you may have some additional issues. Most likely you will be pretty close or even a bit high. I would start eliminating them one by one and see where your results stand.
First eliminate adding extra grains, because that one doesn’t really solve the root of the problem it really just solves the symptom of low gravity. Then I would see what happens when you go back to a 60 min mash not a 90 min because lets face it time is valuable. You might end up just finding out that you need to do 3 runnings not just 2. Hope it helps ya, cheers and keep on brewing.
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July 11, 2012 at 12:59 pm
I would like to add also the following, these will affect the efficiency too – and by correcting them you will solve the root of the problem.
– Check your grain crush. Go with your hands through it, and see if the grain is crushed nicely. If it is not fully crushed because of a mis-alignment of your malt mill, you will go way down in your efficiency. Maybe very obvious, but it does happen.
– Make sure you hit your correct mash temperature(s). I have been brewing all-grain for a long time, and I have had problems with my thermometers. Even scientifically calibrated (at least that was what the manufacturer said, they came from Fisher Scientific) it was a 5 degrees off for both. That will have a huge impact on your mash efficiency and fermentability as well. Also make sure the temperature is stable.
– Mash out, and mash out at the correct temperature. If you go lower, then you will dissolve less sugars, and end up with a lower gravity pre-boil wort. Do not go too hot though. Stick to 170F approx.
– If you fly sparge, do not go too fast. Let it flow, but do not rush to drain your grain. By going to fast, sugar will be left behind on the grain, and your efficiency will be too low.
– If you do not have a fly sparger you could just grab a coffee mug, and keep on dumping 78C (~170F) water on top, and keep your grain under an inch of hot water while you slowly drain using gravity. I used to do this, and it works fine.
– Tweak your water-grain ratio. Some brews call for a more dilute mash, some do not. It will affect your conversion rate. Going a little thicker might get you a better conversion.
– Make sure you vorlauf. It will create a nice grain filter bed, and you will not carry over so many grain particulates in your boil.
– Maybe for more advanced brewers, but if your pH is way off your conversion will be affected as well.
July 11, 2012 at 1:04 pm
All very true. Thanks for all of the input!
July 12, 2012 at 10:38 am
You’re welcome!
July 12, 2012 at 8:30 am
I just started AG and didn’t have this problem, thanks to your series on AG brewing. I thought I was way off at first, but realized I didn’t correct for temperature. I was taking SG readings at 130 degrees and not 68. This put my numbers dead on to what BeerSmith estimated them to be. Thanks!
July 12, 2012 at 10:35 am
That’s amazing! Glad it worked out for you. Early success is so clutch.