Efficiency drop with 6 row or flaked maize?

[pig140]

I brewed a cream ale yesterday and it's my first time brewing with an adjunct and my first time using 6-row. It was a very simple low gravity recipe. I always batch sparge using the double sparge method splitting my sparge water. I consistently get 69-70% efficiency. I noticed the end of the sparge runnings had no sweetness at all. After the boil, I took a reading and thought I had gone a point over, but then I realized we had over-boiled. OG 1.045 (supposed to be 1.044) but we over-boiled and lost a little over a half gallon. The software calculations put me at 63%.

My recipe is:

50% 6-row
28% 2-row
11% flaked corn (which I didn't mill)
8% corn sugar
3% Crystal 10

I know it'll be good beer, I'm not worried about that. I just wanted to know if this is par for either of these additions so that I can adjust next time. The only other difference I can think of is that most of the time I order milled grain from NB or AHS. This time, everything but the 2 row came freshly milled from my semi-local HBS. Mill setting maybe?

 

[Magnus314]

6-row yields a little bit less than 2-row.

And 28% flaked corn probably needs a little longer mash to fully extract and convert to its fullest.

That, and flaked corn seems to hold a LOT of water, so you may have just lost an extra 1/2 gallon to corn-soakage, and need to just up the mash volume by 1/2 gallon next time.

 

[pig140]

Thanks for the quick response! The 28% was 2-row, the corn was 11%, but still I get what you mean. I did a 90 minute mash for this one because I wanted it to dry out. I didn't think about the corn holding the water tho. We had hell getting those last few drops out. I also didn't know that about 6-row. I kept reading to leave the corn unmilled and some places don't even offer to mill it. I can't help but think that might have made a little difference. Maybe several factors together hurt my efficiency?