What happened to my efficiency?
 

I brewed last an AHB Doppelbock on Saturday. I have had the AG kit sitting around for a while maybe 5 months pre-crushed and in the sealed bag. I have been waiting that long to get the courage up to lager.

So I followed my normal routine which usually gets me in the high 70s for efficiency. The predicted OG was supposed to be 1.088. During my initial runoff I had a reading of 20 on my refractometer so I knew I was in trouble. I fly sparge and when I had about 5 gallons in the brew pot I read took a reading and was still getting about 13 brix so I just kept sparging, since I was still getting sugar. I ended up with about 8.5 gallons in the 1.060 range.

I was showing a friend who was an extract brewer my AG setup and techniques. At this point I suggested he go home to finish his own projects as I was in for a long day. I spent a half hour or so cleaning while skimming hot break, took an hour nap on the couch near the kitchen. When the wort was at 7 gallons I added the hops and started my hour boil.

After a very long day I had 5.5 gallons of 1.088 wort in a carboy, so it all worked out perfectly but why was the mash slow to release its sugary goodness?

My guesses:

1. Older grain
   
2. Improper sparge temp for smaller batch (5 gallon vs normal 10 gallon)

Different grains then you are used to using I presume. Sparge temps, you did not mention what they were.

Nap, you can actually take a nap while brewing? Doubt I could ever be that relaxed to do so.

Have you done a strong beer before? You will generally get lower efficiency with a larger grainbill.

Probably not the sparge temp, as it has very little effect on efficiency.
http://www.homebrewtalk.com/f36/cold-water-sparge-110856/

I had to work late the night before, and was on call till even later. Then a family pet decided I should get up at 6am, nap was easy. Also I was figuring on a 3 hour + boil, didn't make sense to stare at a boiling pot while fatigued that long.

I was definitely using diff grains from my usual. I almost exclusively brew with Western 2-row as my primary grain but this had mostly Munich with some Pilsner 2-row.

Most of my beers are big beers but this is my biggest AG yet. It was about .015 bigger than average.

I think sparge temp had a factor in it. I use a sparge arm and it looses quite a bit of heat. I was still getting decent efficiency before, but was probably sparging too low. I had finally stepped up the temp to get the desired temp in the grain bed. Maybe the extra head space in the 5 gallon batch and the further drop from the sparge arm caused more heat loss.

One issue that seems strange though is my first runnings were low. I am used to the first runnings exceeded the expected OG and the last runnings to be low. Together they should add up to the OG (minus boil off) when you have the pot filled with your preboil amount.

It is not like i did not get my target OG I just had to sparge more than I would have liked, and boiled longer than I would have liked.

So maybe sparge temps is not it but reading that thread i got a possible answer. Smaller grain bed, possible channeling and too fast draining leading to low efficiency in my 10 gallon MLT. I had done a few 5 gallon batches when I first started AG with this MLT, but my last 4 batches in which I have been dialing in the system were all 10 gallons.

Yep, the height to width ratio of the grain bed is an important factor when fly sparging. The added distance the water was dropping from the arm may have caused it to impact the grain bed harder and contributed to channeling as well. I don't know a lot about the specifics because I'm a batch sparger.

Did u said you were suposse to get 1.088 and you got it? Then whats the problem?? Having such a high gravity like this and reached it is for me, a succes.

I agree it was a successful brew day. I just hope to not have to have 3+ hour boils in the future to make my day a success. 2 batch days are a long ways off if each batch is going to take me 8 hours.

I would also think using older crushed grains that sat for months would make up for small amount of efficiency loss. 5 months is long time to me, though. I'm on edge if I have a crushed bag sitting for 5 days.