Help me understand what happened.

I have a couple of successful (74% and 75% efficiency) brews under my belt.

A friend of mine invited me up to his place yesterday to show him the ropes as I had all of the necessary equipment.

To give you the real issue first, he bought the crushed grain at our LHBS well over a month ago (which I did not realize until after our brew day was nearing completion)

The mash went well 152 degrees for 60min
(temp check at 60 min mark was still right about 151)

Forgot to check gravity of all the runnings until the end when I noticed that it was coming in at 1.025 pre boil
(which was when I started asking questions and found out about grain age)
(I checked the calibration of refractometer at this point and it was accurate)

Boiled for 60min and got it up to 1.036 (recipe OG was supposed to be 1.057)
I did happen to have 1# of light DME on hand (which was learning point #36 per my friend), and got OG up to 1.045-ish (in about 5.25 gallon post boil)
I discussed boiling it more to get it up a little higher, but time was our enemy and we had to finish up.

So my fairly NOOB questions are
1) Did the grain age play a HUGE role in this? It was in a brown paper bag and kept in his garage for the entire time where it experienced a lot of temperature fluctuations mostly cold.....

2) Was there something else that we could have possibly done wrong? In the mash perhaps?

I thinking that the resultant beer will be less abv that expected?
The color on it was great and the taste was equally good.

What do you think?

Biggest change was probably the water. Changes in water chemistry can lead to incomplete starch conversion and lower og

I would question that he purchased the right amount of grain.

What did his crush look like, that poor of efficiency starts with a bad LHBS crush, then water PH

Same crush as my batches where efficiency was in the 70's

pH could be the culprit... we used his water and not my usual.
Oddly enough, I discussed the water profile with him as we were brewing.

I will have him check that out for me.

So are you saying that the age of the grains is not as critical as I might have thought?

How different was the water from yours?

ETA: If not the crush, I doubt water would make that big of a change. Bad thermometer? Reading 152 but off by 10 degrees?

Correctly stored crushed grain can last up to 3 months

cfonnes said:

I would question that he purchased the right amount of grain.

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I would also have to agree given that my recipes have both been 12# of grain and his was 11#, although I did not think that 1# would mean that much less fermentables.

and no, I would not know a good crush.

Just went on the premise that i had good results from 3 batches and that meant to me that I was getting a good crush.

brewkinger said:

and no, I would not know a good crush.

Just went on the premise that i had good results from 3 batches and that meant to me that I was getting a good crush.

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Maybe yours were crushed correctly and his wasn't?

I would have to say crush or wrong thermometer.