Efficiency Question

I am mid boil right now. Maibock recipe from Braukaiser.com. Or as close as I'll get to it today. Bear with me:

8.5# Pilsner Malt
3.75# munich
1# Cara Pils

Combination Infusion/decoction clustermash
150F 40min
157F 30 min
168F mashout and lauter at 1 qt./min

6gallons pre-boil S.G. =1.062
Gravity of last runnings (as I shut down lauter)=1.030

My numbers are telling me that this would be ~85% efficiency

Is that possible with so much sugar stillin the MLT when I'm done. Should have made a small beer with the waste.

Maybe I'm wrong, I'll update with the actual OSG and volume.

So I ended up with 4.25 Gallons @ 1.074 OSG Which I think means:

Total gravity points in grain bill= 432.5
432.5/4.25=102
and 74/102= 73% efficiency

I guess I'll collect more wort next time, lost a lot to steam.

I just ran those values through the calculator.
8.5 * 38 = 323
3.75 * 37 = 138.75
1 * 33 = 33
323 + 138.75 + 33 = 494.75
494.75 / 6.00 = 82.458
6200 / 82.458 = 75%

That's certainly reasonable with the last runnings at 1.030

-a.

That seems like you are around 73.5% eff. If that's a 5 gallon batch, I calulate OG at 73% eff at 1.074 which equals 370 gravity points. If you have 6 gallons at 1.062, then you have 372 gravity points. If you divide 372 by 5 gallons, you'll get an OG of 1.074... is that what you're shooting for?

Damn! That was quick! I though I was being quick, but I am a little buzzed right now - just watched Beerfest for the first time and had to join the festivities

Yeah I was shooting for 5 gallons. Ended up with 4.25, not really sure what happened. Why would there be such a big drop in efficiency by boiling? 73% is just fine by me, it's my third AG brew. I would like to work out the kinks though.
As a side note, I got totally hosed with pellet hops. The HBS didn't have the whole hops I wanted. The sludge clogged up my pickup tube so I had to manually scoop out the wort and strain it. Plus I was worried about volume so I got greedy. Lots of trub. What do you think? Secondary?

Well, your mash eff is still the same. That is, the amount of potential sugars you pulled out of the grain. Remeber - you have mash eff and system eff. System eff takes boil volumes, equipment loss and other factors into play. The fact you pulled 6 gal at 1.062 means you pulled ~73% of sugars out of the mash.

At the end, you probably did have 5 gallons at 1.074, but then lost .75 gallons somewhere in the trub/kettle/strainer. Your gravity would have stayed the same, but your volume would be reduced.

As far as the secondary, I've always been an advocate, but lately, I only secondary if I'm dry-hopping or aging extensively. I believe there's more benefit to leaving the beer on the cake (diacetyl clean-up mainly) than there is potential danger.

Are you using brewing software? If not, I highly recommend ProMash. Then I would use a simple water test to check your equipment loss. Treat your equipment like you would when you brew (i.e. don't tilt pots to empty unless you do that when you brew). Knowing all those parameters will ensure you get the brew you want when you set off to brew. Also, develop a precise way to measure volumes and gravities in all of your vessels along the brewing path. You won't have to take them forever, but if you do it a half-dozen times, plug the related numbers into your brewing software (or tuck it away in you noggin'), you'll have your method down pat.

Hope that helps