Efficiency woes, can't figure it out... feedback?

Hi, I've been doing all grain 5gal batches for over a year now. I was hoping to describe my process in detail and get feedback on why I may be experiencing low efficiency.

Specifically, I can't seem to get my 5gal OG above about 1.055 no matter how much grain I use. If I'm going for a beer from 1.045-1.055 OG I get fairly decent efficiency, 65-75%, and usually hit within my target OG range (+/- .003).

However, anytime I try and make a bigger beer I can't seem to really crack 1.055 or so. Sometimes I'll get a little higher, but nowhere near 70%. I have to use DME or sugar to up the OG.

My process is as follows. I'll use my latest beer as an example (an oatmeal stout).

Grain bill:
9lbs 2-row
2lbs c80
1lb flaked oats
.5lbs chocolate
.5lbs roasted barley

Mashed at 157* for 60 mins in 4gals of water. Mash tun is a 10gal SS pot fitted with a false bottom. Rested around 158*, put the pot in a warm oven to keep it from losing temp, and finished about 156-157*. I then pulled it out of the oven, stirred thoroughly, put the lid back on, and let it rest another 10 minutes. Drained first runnings and put on the flame.

Batch sparged with 3.5gals 190* water (to bring the sparge to 170*). Stirred thoroughly. Waited 10 mins, drained second runnings added to first runnings and brought to boil.

Went through the 60 min boil, cooled in about 35 minutes with immersion chiller, transferred to carboy. OG: 1.054. At 70% efficiency should have had around 1.065.

Again, it's weird because I can seem to hit 70% eff. for smaller beers, but not bigger ones. I ended up with close to 5gal as I should have, so it's not as if I had too much volume.

Adding more grain doesn't seem to change it much. If I use 6lbs or 10lbs of 2-row, I still get about the same OG.

I don't really mind doing partial mashes for bigger beers, but I guess I'd prefer to figure this out if possible.

Any ideas?

 

A couple of things that seem to effect my efficiency are:

1 - If I run off my 1st runnings and sparge too fast my efficiency goes down a tad. I slow it down and it helps.

2 - If I do a single batch sparge instead of a double, then my efficiency goes down a tad (especially with bigger beers)

just a thought...

 

Sorry, lack of coffee this am. Misread your post a bit.

 

You had me confused there...I hit the quote button and it brought up your edit.

To the OP, have you taken gravity of your final runnings? They should be in the 1.010 range. You probably just need to sparge with more water. Have you done a starch conversion test (probably not the issue given your mash temp, but just a thought)?

 

A few basic, general options:

Get a finer crush on your grains or just double crush them. If you're worried about getting a stuck sparge .5 lbs of rice hulls is plenty to keep you from getting stuck.

Check your thermometer to make sure you're getting an accurate reading.

If it's accurate, mash at a lower temperature. In general, a lower mash temperature will get you more fermentable sugars. Also, longer mash times can give you more sugars.

Stir more to make sure the mash is mixed well and there are no dough balls. The basic tenet of this is "stir like it's your job".

 

I've been thinking about this one a bit. Seems like your volumes are off somewhere.

How much are you getting on your first runnings? I'd say you're lucky to be getting 2 gallons (and quite possibly less). Only having 3.5 gallons to sparge with is going to leave you short on volume, not to mention leaving a lot of sugar behind with not enough volume going into the boiler. I don't see you getting 6.5 gallons into the boiler with those numbers. So, you're not boiling off much and concentrating your wort at all.

Going from 6 to 10 lbs of base malt is going to raise your gravity, even with a crappy crush. You're leaving it behind somewhere.

 

I haven't measured the first and second runnings. I calculate the water based on estimating 1-1.5gal absorption during mash, and 1gal evaporation during boil, for a total loss in this case we'll say of 2.5gals.

By using 4gal in the mash, and 3.5 to sparge, that's 7.5gals total, with 2.5gal lost approx, which gives me the 5gals. It has more or less stuck me in the right ballpark for finished volume. If I'm making a hoppy beer I'll add an extra .5gal est. for water absorption there.

Do you think it would be worth it to increase the mash volume and boil longer to evaporate down another .5-1gal? Not sure I'd like an extra hour of boil time but I could try it...

 

I haven't done gravity readings on my runnings either. I think maybe I need to measure the runnings and take gravity readings to try and figure out a step that is lacking.

 

Very odd!!!

 

In order for you to be getting 6.5 gallons of runnings into the boiler, you need to be getting back 3 out of the 4 gallons you mashed in with as first runnings. Don't see that happening.

Next time, run off your mash into a graduated white bucket. Subtract that from 6.5 gallons and sparge with that amount of water. It would probably be better for you to split the sparge water in 1/2 and do two equal sparges, at least until you get a handle on what's going on.

 

Still being a Newb you can take the three adjustments I have done for what its worth. But these last three adjustments have my Eff. around 80%.
First was to take to heart "Crush till your scared" & "flour is a good thing" I make sure I get a good fine crush. I was frightened of stuck sparges, torn husks or flour junking up the works, but it hasn't happened so far.
Second is I mash with 1.5 qts/ lb. Made sense to me after I started doing it. Your trying to get the sugars out of the grain and into solution and into the pot. The weaker the solution the more sugars it will hold.
Third was to add my sparge water stir wait 10 minutes and drain the sparge very very slowly. Maybe 30 to 40 minutes. First as not to create a stuck sparge and second is to again allow the sugars to get into solution.
I pretty much contribute my early sucess to countless hours of studing post from this forum and any other resource I can find. Maybe its just luck.

 

Sorry to hear about your brewing woes. When I first went to ag that was me too. I couldn't get a eff above 60%. Two things I did that get me now in the 75% range. 1 Is crush, I know its a dead horse but my crush has to be very fine.

Also, I have since realized my digital thermometer is ten degrees off. So if it shows 152 its probably 142. So now I know. Check your thermometer in ice water and boiling water. Also if you have a old fashion thermometer you can calibrated the digital one.


My lhbs has a horrible crush. My buddy bought a cheap corona mill and although its a pain the efficiency makes it worth the money.

Hope it helps. Cheers!

 

Ditto what DHack61 says up there. I started stirring really vigorously at mash start and then twice more during the mash and my eff went up a lot. I also use 1.5 qts per pound consistently now, and that makes it easier to stir. My dial thermometer was off by 5 degrees, now I use two digital themometers, they keep an eye on each other and I keep an eye on them!

 

Thanks for the suggestions. I'm going to try some of these ideas, particularly 1.5g/lb and two sparges.

 

Not to overwhelm, but mash ph has a lot to do with efficiency as well.