High mash efficiency problem
I brewed a cream ale yesterday afternoon. The recipe:
5 lbs 2-row
5 lbs pilsner
1 lb flaked corn
12 oz. corn sugar (added to boil)
Mashed for 60 minutes at 152F
Batch sparge to collect 7.5 gallons wort for a 90 minute boil.
1.5 oz Crystal 3.5 for 60 minutes
Here's the problem: my mash efficiency was over 90%! My pre-boil gravity was 1.047 at 85F (1.050 at 59F) for 7.5 gallons. The recipe was planned with an expected efficiency of 65% which is in the ballpark of my last couple batches so I was expecting a pre-boil gravity of 1.035. Obviously I missed by a long shot on the high side. I tried to compensate for the higher gravity by adding 2.0oz of hops for 75 minutes vs. 1.5 for 60. This was all the hops I had on hand so I'm not sure how much it will help. I boiled down to 5.5 gallons, transferred 5 to the carboy and topped up to 5.5. My OG is 1.061 as it stands. This is going to be a high ABV cream ale!
Anyhow, I'm wondering why this happened? I checked and re-checked my numbers but, based on my OG, I was correct with my pre-boil gravity reading. The only change I made in my system was to use a copper manifold instead of the braided tube of my past batches. I switched because the braid used to move around alot and wouldn't sit on the bottom of the cooler (A 5 gallon round Rubbermaid). I'd find a lot of wort left over in the bottom of the cooler because of this. The manifold solved that problem, maybe too well.
Any ideas? Was it just the manifold change? I'd like to be in the 75% range for efficiency, not 90. I'm afraid I might get a grainy, astringent taste because of this. I'd also like to plan future brews with an adjusted efficiency but don't want to use 90 because it may have been a fluke.
Sorry for the novel and thanks for any input.
Primary 1 - "March in May Cream Ale"
Primary 2 - empty
Bottled - "Four Ones Alt"
Kegged - "666 - The Number of the Wheat"
Crying Over - "Triple K Lager" that went down the drain