Extract efficiency calculations

I've always been curious about my extract efficiency. I dug around and read several articles about it. A lot of them are just flat out confusing. I found a pretty basic one, that explains the breakdown like this:

1. Multiply the amount of grains you used by the potential maximum extract from your grain. You can find them online, here's a list of some popular grains (click here), I didn't see my Maris Otter on there, so I just googled "maris otter extract potential" and several sites came up.

2. Once you have these numbers, multiply them by the amount of grains you used. So, with my most recent IPA i brewed, here's the breakdown:
20 lb Maris Otter x 38 = 760
4 lb Munich x 37 = 148
2 lb Crystal x 34 = 68
===============================
976

3. Take this final number, and divide it by the number of gallons of wort you collected, in my case, I collected exactly 12 gallons. 12/976 = 81.3 points

4. Next, and this part is tricky, but bear with me: Take your specific, pre-boil gravity number, mine, was 1.072. Take the last two numbers, and and divide your total points from step 3 by this. So: 81/72 = 88%

I'm guessing this is how it's done. After reading several articles, I think I have this all together right. Correct me anyone, if this is wrong.

But 88% sounds pretty good to me. I was wondering how I was doing in this area. I know there are a lot of factors that can effect the efficiency. Using a refractometer, crushing the grain better, proper sparging temperatures, etc. Here's a thread with some interesting tips on boosting your extract efficiency - (click here).

Finally, my first all grain IPA

Last Friday I took a vacation day and brewed a 10 gallon batch of IPA. I split the batch in two - here's what I did:

20lbs Marris Otter
4 lbs Munich Malt
2 lbs British Crystal

I split the batch because I wanted to try out some homegrown hops I received (Willamette I believe). In the first batch, I added 1 oz. Summit (60), 1 oz. Ahtanum (15), 1 oz. Simcoe (5), and will be dry hopping with 1 oz. of Argentine Cascades. The other 5 gallons, I added 1 oz. of Summit (60) and a bunch of the fresh dried home grown hops (15).

California Ale yeast - starter made a couple days before.

This brew went surprisingly well. I started at 5 a.m. and things went like clockwork. My mash tun was filled to the top when I put the lid on. This time I put towels over the top of it, thanks to a tip from a Beer Advocate member - it really helped keep the heat in. After an hour I started draining the wort into the split batches.

I boiled and followed the hop additions as seen above. I really need to get something for my keg boil kettle, a screen or something at the bottom, because the whole leaf hops got all stuck when syphoning the wort out.
Anyhow, I'm going to dedicate the fresh hops batch to Leon Blackburn, who's wife donated a bunch of their hops to us. Leon passed away in June of 2007. He grew some amazing hop vines a while back and this year the crop was huge! I'll be doing a post on the MiBeerBuzz.com blog when the beer is finished.

Hoppy Fall IPA: Pre boil gravity - 1.072
Post boil gravity - 1.082

Blackburn IPA - Pre boil gravity - 1.076
Post boil gravity - 1.084

The difference in the gravity between the two was a mistake on my part. I was doing one pitcher in one boil pot, then another in the second boil pot. Well, I did two in a row in the Blackburn IPA.. oops! My other mistake was coming out a bit under 5 gallons on both of them. The Hoppy Fall IPA came in around 4.5 gallons, the Blackburn IPA was just under 5. I didn't top them off with water, I feel that kind of messes with the whole batch by doing that - but I did learn, a 6 gallon boil will reduce to a 4.5 gallon wort after an hour - so, I'll probably shoot for 6.5 gallons of wort to boil next time.

Anyhow, the room these carboys are in smell freaking awesome. I can't stop walking in there every few hours and smelling them. I'll be racking the Blackburn IPA to a secondary for a week or two of settling and the same with the Hoppy, but I'll be dry hopping that one at some point. mmm. Hops. Oh yeah, the odd hops I used were the ones free from the AHA rally I went to. Somehow I wound up with 3 bags of hops. The Summit hops were the only ones I had to purchase. This whole batch cost about $55.00.

Hops

I just inherited some hops and they smell awesome. I can't stop playing with them. Anyhow, tomorrow I'm going to begin sealing them up for freezing and giving away. Here's a pic of them.. they smell wonderful, I wish I could blog smells, but, Google hasn't invented that yet. I should register googlesmells.com so when they invent that technology, they'll be able to buy the domain off me for TONS of $$ .. :)