Sparge Volume

Last week, I brewed my first all-grain batch and ended up with too much wort. I was brewing a 5 gallon batch of Alt, but ended up with way too much wort (close to 10 gallons) after sparging. I'm trying to determine my mistake so I won't replicate it in the future.

My recipe had about 12.5 lbs of grain. I used a 1.25 ratio of water to grain for my mash. This meant 4 gallons of water in the mash. I added 8.8 quarts of boiling water for my mash-out (I calculated this as the minimum amount of water to add to bring me up to 170). At this point, I had hit my target temperatures exactly and was feeling pretty good about myself.

I'm pretty sure this is where things went wrong. I've read both Palmer and Papazain's books and both recommend 2 quarts of water per point of grain. For my recipe, this required 6.3 gallons of sparge water. As I stated earlier, I then ended up with nearly 10 gallons of wort after doing this.

Fortunately, my efficiency was around 82%, which allowed me to salvage the batch. I ended up with an OG of 1.045 rather than the 1.066 I was going for, but I'll still end up with beer rather than tossing the batch.

Naturally, I don't want this to happen again. I'm thinking that I need to subtract my mash-out volume from my 2qt/lb sparge ratio, but don't know if that was my issue or not. I like to brew high gravity beers, so I am wondering if the 2qt/lb sparge ratio stays the same as the amount of grain rises? Looking for some advise in this matter so I can feel more successful at the end of my 2nd batch this weekend!

Did you boil down that 10 gallons of wort to 5 gallons?

Really need to see the recipe and know a bit about your setup to dig into your issue.

Are you batch sparging? If so go to brewheads.com and use their calculator. It's awesome. Ideally you calculate your volumes by the total pre boil volume you need, divide that in half, then add half a quart per pound for absorption. Plus any system loss you would have in your tun. Add the first half plus loss and absorption amounts and go to town on your mash. Then sparge with the second half. Hope that sounds correct.

What was your final volume? Sounds like if you undershot your og, you needed to boil longer. That would increase your og.

Brewsmith calculates all the water volumes on my behalf, but whenever I brew a recipe I haven't created myself I use the lazy man's rule of thumb, provided by my LHBS:
Mash with 1 litre of water per pound of grain (for imperial, I believe 1 gal = 4 litres? So... divide pounds of grain by 4 for mash gal's)
Sparge (batch or fly) with your final batch volume (5 gal)

Essentially, the mash volume boils off and sparge volume remains. This is probably bad advice for those that are concerned with efficiency and such, but my beer has always turned out well using that rule of thumb which is the proof in the pudding.

I should have taken the time to boil down to around 6.5 gallons, but I didn't have it. I was also concerned about the potential for off flavors if I continued to boil for the extra hour(s) it would have taken to reduce the volume. I boiled it down to around 8 gallons and put 5.5 into primary. Hence, the lower gravity. I know what to do if this happens again, but am really concerned with preventing it in the first place.

I'm wondering about calculating the sparge volume after conducting a mash out. Should I subtract this volume from the suggested 2qt/lb ratio or is this ratio too high in the first place?