big brew, pathetic OG, WTH?

[scottlindner]

This weekend I brewed the biggest brew I have ever attempted. It's a Belgian Dark Strong Ale with a ProMash estimated OG of 1.110 assuming 75% efficiency. I have been out of brewing for a couple of years and just recently got back into the game again so there is some rust in my memory. The OG came out to 1.084, that's 0.026 (24%) below the target. That's some serious inefficiency. Back when I was brewing every week several years ago my efficiency was in the low to mid 70s so I should have been close to the target.

Some things that could have gone wrong.

1. I do the boil outside and just by chance brew day was a blizzard. I cowered inside. I can tell I missed one massive boil over, so that's certainly a potential loss of sugars.
   
2. I didn't accurately measure the wort volume after the boil but I'd say it's in the 4.5 to 5.0 gallon range based on the boil marks on my kettle. The target was 5 gallons.
   
3. I had some big temperature issues in my mash. I recently switched thermometers and I think I'm not used to the speed the new thermometer reacts. My mash hit 158F before I realized it was that high, so I threw in some ice cubes. Only later to find I knocked it down to 144F. I'd say I had 50/50 time at the high mash temp and low mash temp.
   
4. I use a Barleycrusher and since the grain bill was nearly 20lbs I used a drill instead. I ran it a fairly high speed. Could this have caused a poor crush leading to an inefficiency?

What are your thoughts? I know there are a bunch of mistakes I made that could be improved, but 1.084??? I gotta know what caused it to be so low so I don't repeat. According to ProMash that's a 56% efficiency. Blech.

I know this is a common topic and I'm familiar with the common issues. Typically milling problems. I suppose that could be it. Several years ago I wasn't using the Barleycrusher, I was getting my grains milled at the LHBS when I was hitting the low to mid 70s.

Scott

 

[BigEd]

Effeciency drops with high gravity beers. If you are used to getting 75% on standard gravity beer expect a 10-15% drop at the 1.100 range.

 

[aaronwillen]

although I have never done such a high gravity brew isnt it standard practice to increase the sparge water a bit then increase the boil length to compensate? How do you know how much to increase the sparge water btw?

 

[sirsloop]

Yeah, increase sparge water and boil longer. You could have easily done an extra 1-1.5g of sparge and boiled for 90-120min. Another option would be to accept the low efficiency and do a partial mash by adding in ~3lbs pale DME... or more grain if you have the capacity.

 

[scottlindner]

although I have never done such a high gravity brew isnt it standard practice to increase the sparge water a bit then increase the boil length to compensate? How do you know how much to increase the sparge water btw?

I did a 90 minute brew and compensated for the sparge water accordingly.

 

[scottlindner]

So it appears that most of my inefficiency is due to the high gravity. I hadn't heard that before but it makes sense now that I think about it.

Next time I brew this recipe I'll shoot for a 120 minute boil and see what happens.

Scott

 

[BigEd]

So it appears that most of my inefficiency is due to the high gravity. I hadn't heard that before but it makes sense now that I think about it.

Next time I brew this recipe I'll shoot for a 120 minute boil and see what happens.

Scott

As has been posted above the sparge water ratio used on a normal gravity beer doesn't work on very high gravity brews. You can live with it and add more fermentables or increase the sparge water beyond the standard amount and boil away the excess.