80% efficiency - but missing my target OG

[gonzo brewer]

So I have worked out the bugs of my AG equipment and went from mid-60's to 75, 80, & 83% efficiency based on a pre-boil volume of around 7 gal.

Yesterday I hit 80% efficiency but missed my OG by 6 points. Heres the data:

Irish Red Test
8 lb. US 2-row
1 lb. Munich
.5 lb. Crystal 40
.5 lb. Crystal 80
.5 lb. Victory
.25 lb. Cara-pils
.125 lb. roasted barley

60 min mash in a coleman 48Q cooler with copper slotted manifold.
Mash at 154º I use PH 5.2
Add 2 Q boiling water to get grainbed up to 161º, stir good and let er rip.
1st mash out @ 1.063 SG
two equal size batch sparges of 2-1/2 gal of 175º water - grain bed up to 167º
last sparge runnings @1.022
Collected 7 gal pre-boil @ 1.045 SG
My evap rate is quite high. 60 min boil and I'm down to about 5.25 gal.
My measured SG post boil is 1.052. This is 6 points off my beersmitch calc.
I have efficiency set at 78% in beersmith. I mash at 1.3 qt/lb.

I don't get it. If my eff is up there, I should be hitting my target OG of 1.058, but only got 1.052.
My previous Brown was 2 points higher. Previous to that, my stout was 4 points lower. Previous to that my Hobgoblin was right on at 1.056
What am I doing wrong?

 

[david_42]

If you miss your OG, your efficiency isn't as high as you have it set in the calculator. Looks more like 72%. How large was your first runnings?

 

[FlyingHorse]

Either something's off in your volume measurements, or you're losing some volume to something other than evaporation.

7 gal preboil at 1.045 would give you 5.25 gal post-boil at 1.060, if you didn't lose anything but evaporated water.

If you went from 7 gal @ 1.045 down to 1.052, you should have 6+ gallons left. So either your volume measurement in the primary is off, or you lost 3 quarts of wort somewhere between the kettle and the fermenter.

 

[Brew-boy]

When I ran your numbers I get 73% , Glad I don't batch sparge any more I had to many ups and downs. I only fly sparge and get a constant 82-83% efficiency. Set your efficiency to 73% in beersmith and do 2-3 more batches and see what you get.

 

[gonzo brewer]

I mashed with 4-1/2 gal. and collected about 2-3/4 gal. 2-1/2 gal 1st batch sparge, 2-1/2 gal second sparge, but stopped running after I reached 7 gal pre-boil.

I do my eff calculations on an excel spreadsheet. Is there a place to do them in beersmith?

I measured my loss (1-1/2 qt) at the bottom of my keggle after draining to primary. I lose 10-12 oz to hydrometor measurements post boil. My boil pot keggle does not have a sight glass, so I estimate pre-boil with sharpie markings on the outside of the kettle. I figure I'm within 1 qt.

I need to make a measurement stick for my 6-1/2 gal carboys and my 5 gal carboy.

I think I need to tighten up my volume measurements. I'll try this and set my eff lower in beersmith.

 

[Bugeaterbrewing]

I got rid of the inconsistency of preboil volume measurements by sparging into a bucket with measurements marked every half gallon. I then transfer from the bucket to the boil kettle. If you try this, don't trust the measurements that are sometimes premarked on the bucket (such as the "Ale Pail") as they can be off quite a bit. You need to pour in measured amounts of water and mark them yourself.

Another advantage to thsi system is that you know exactly how much water to use for your sparge after your first runnings. (assuming you batch sparge.) You only need to get your calculations somewhat close for your dough in. You don't have to mess with pinpoint accuracy at that point.

Wayne
Bugeater Brewing Company

 

[PseudoChef]

Are you taking measurements with a hydrometer?

If so, are you using a temperature correction from Beersmith or are you waiting for the sample to cool? This could lead to some inconsistency.

 

[BierMuncher]

My efficiency varies with the size of the grain bill.

I just discovered that if I mash for 80 to 90 minutes instead of 60, I pick up about 4-5 gravity points.

Who'd have thunk it...