Ok, this is my 2nd batch where my mash efficiency has come in, in the 90's.

I use beersmith to calculate my recipes.

I've brewed 5 batches this year. My mash efficiencies have been 83.3, 83.1, 89, 97, and 92.6. I've used 5.2 stabilizer in my last 4. However, my second batch this year (83.1), 5.2 wasn't thrown in until 30 minutes into my mash (forgot about it).

My second to last brew, an oatmeal stout, had a very high mash efficiency. My mash efficiency, according to beersmith, came in at 97%. I had a typical 60 minute mash and 60 minute boil. My brewhouse efficiency came out to 82.8% and my total efficiency was 82.5%. When measuring my OG, i came in 10 points higher than expected. My FG also finished 10 points higher. The beer tastes great, but the higher than expected gravity and efficiency is throwing off my recipe planning.

My last brew, a christmas IPA, was somewhat new to me. First, i mashed for 70 minutes for the first time, and conducted a 90 minute boil (first time). My mash efficiency came out to 92.6%. However, i planned for a 5.5 gallon batch, but only came out with 4.5 gallons @ 97% eff. So i added 1 gallon of water to the fermenter and my efficiency went to 92.7. My OG, like my last batch, is 10 points higher at 1.078 (instead of 1.068). If history stands corrected, my FG will be 10 points high as well at 1.022, which is not what i want.

My hydrometer is calibrated correctly, and I have not had anything go wrong on my brewday. The only thing i can think of that might be going on, is the 5.2 stabilizer is causing my efficiency to be higher than estimated.

Below is my recipe and my results from Brew Day Saturday.

11 lbs. 4 oz Maris Otter

1 lb 7 oz. Caramel Malt 60L

14 oz. Caraamber

9 oz. Rye

Pre-boil volume = 7.2 gallons

Pre-Boil OG = 1.072

Post-Boil Volume = 4.5 gallons

Post-boil OG = 1.088

Added 1 gallon of water to fermenter

5.5 gallons at 1.078

My original target OG, according to beersmith was 1.068

I use a 9.5 gallon brewpot, a 10 gallon igloo mash tun, and a 10 gallon igloo sparge tank. Fly Sparge

My brewing techniques, grain supplier, and brew water has not changed.