Jump in efficiency

I just did my 9th all grain today. Up until the last 4 batches I used the LBS grain mill for the crush. I have gotten between 68-73% efficiency. After I used my own corona mill the first 2 batches were the same but the last two were over 80. Now the only difference with the last 2 was mash time. I got stuck in traffic and ran late on last weeks brew. It mashed for 2 1/2 hrs and I got 81.5% efficiency. Today I figured let me see if this works again and did a 90 minute mash. Well I got the same 81% efficiency today. I thought conversion should be done around 60 minutes. I did a search and came up with people talking about a 20 minute mash? Im kind of confused and will end up with a stronger brew which is ok but if I can use less grains great. Oh also all mash temps were between 150-153 for all the brews so I dont think this had a big effect on the efficiency. Thoughts .

I found that when starting, my efficiency gradually increased as I got used to the process and equipment. Eventually, my efficiency stabilized. I got a Corona mill so I didn't have to buy pre-crushed grains by the pound, but this didn't make any difference to the efficiency. (I used to get a good crush from the LHBS).
I got a roller mill, and this saved me a lot of time, but again made no difference to efficiency.
I then started doing a mash out before fly sparging. This gave me a consistent 10% increase in efficiency, but occasionally gave me astringency problems with low OG beers until I learned to monitor the gravity of the sparge runnings and stop the sparge when the gravity dropped below 1.010.
Then, I switched from a 5g MLT to a 10g. My efficiency instantly dropped by 5%, and it took me about 20 - 30 brews to recover that 5% as I gradually got used to the new MLT.
I used to mash at 153-154F for 60 minutes, but I changed to mashing at 150F for 90 minutes. Any difference in efficiency caused by this was too small to be measured, but it did make a noticeable difference to attenuation.

-a.

Are you doing a conversion test using iodine? It's not an exact science but it be able to help see whether you've fully converted after 60 min. Some people swear by this method others don't buy in so much.

I personally have just done 60 minute mashes and hoped for the best.

More than likely your improved efficiency would have something to do with crush, mash volumes being off a little, the grain bill (grain type as well as grain bill size), etc. Start checking off those variables first.

On the plus side, you're getting higher efficiency which is the opposite of most people.

I was just about to start a post just like this. I have been doing all grain for 6-8 months, and hadn't bothered to calculate efficiency until recently. I would do kits and recipes and OG typically ran 2-3 points low. Figured that as long as it was consistent, I was OK with it. Yesterday I decided to measure efficiency as I'm more comfortable with the process. I also did a mashout, because that is what the recipe called for. Double batch sparged WOW. I was 8 points over and had a larger volume. I have been crushing my own grains the whole time. So, the mashout was really the only difference. Calculated Efficiency was 76%. This was a big beer so the extra points will go well, but I guess I will need to calculate each time so be able to predict better.

ajf...I should have also told you that I fly sparge. I do the same with the runnings and if I have to stop early (lower then 1.01) I would. I have never had to stop early though. I always mash with 1.25 qts. per gallon and also do a mashout. I have done this on every brew so far. Once I underestimated mashout and had to add more water. The grain bill makes since as when I made Dennys Rye my efficiency was the lowest of all my brews at 68%. This would explain the low efficiency on that brew as it has a bigger grain bill. The last two were an ESB and an Oktoberfest. The ESB had a 10lb. grain bill = 81.5% efficiency. The Oktoberfest had a 14.5 lb. grain bill = 81% efficiency. Im going to keep mashing like I do now and see if it stays the same. As for the iodine test no I have not done one. Thanks for the insight.

wheels, ajf, how do you guys mashout. Adding hotter water or adding heat? do you think it makes a difference, how you mashout? Yesterday was my first attempt and I just used a heat stick in the mash, constantly stirring.

I mash out with boiling water. There are two reasons for this.
1. I mash thick, and the extra water thins out the mash and helps to prevent stuck sparges.
2. It is the only way I have to apply heat to my MLT without melting it
I don't think it makes any difference how you apply the heat, but I do think the stirring assists in the raising of the efficiency.

-a.

ajf said:

I then started doing a mash out before fly sparging. This gave me a consistent 10% increase in efficiency, but occasionally gave me astringency problems with low OG beers until I learned to monitor the gravity of the sparge runnings and stop the sparge when the gravity dropped below 1.010.

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I'm intrigued...how do you monitor the gravity of your runnings while sparging? Wouldn't gravity readings at 170-180 F be pretty inaccurate (with temp correction)? I've always cooled mine in the fridge or freezer and by the time it's cool enough to read (about 80F) I've already started my boil. For that reason I quit taking gravity readings until after my boil.

heckels said:

I'm intrigued...how do you monitor the gravity of your runnings while sparging? Wouldn't gravity readings at 170-180 F be pretty inaccurate (with temp correction)? I've always cooled mine in the fridge or freezer and by the time it's cool enough to read (about 80F) I've already started my boil. For that reason I quit taking gravity readings until after my boil.

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I use a refractometer which only requires a 1 drop sample size. When you add one drop of wort to a room temperature refractometer, it cools down very quickly, and you can judge the gravity of the runnings within a couple of seconds.

-a.

I had always wondered what the true advanage of a refractometer vs hydrometer was...aside from wasting less beer for gravity readings. This may need to be added to my wish list.