I need some input about Mashing.

[y2jrock60]

My brew buddy and I currently mash in a 50 quart rectangular shaped cooler with a CPV manifold. When doing 5 gallon batches we try to keep our beers Original Gravities below 1.070 due to the size of our mash tun. We usually mash with a 1.25-1.5q ratio of water to pound of grain and end up sparging with ~6gallons of water. Our efficiency is pretty consistent, + or - a point or two from Beersmith.

Whenever we make 10 gallon batches we have to use a 1.0 mash ratio due to the size of our mashtun. We max out at about 25lbs of grain with a 1.0 mash ratio. There is very little head-space when we use that much grain. We usually sparge our 10 gallon batches with ~8 gallons of water. Our efficiency is usually higher when doing 10 gallons batches. Usually 2 points higher than what Beersmith says we should get.

Last night we decided to brew a 5 gallon batch of a Double IPA. The recipe called for 20lbs of grain. Due to 50 quart limit on our mashtun we had to mash with a 1.1 ratio. This is the same ratio we use for most of our 10 gallon batches. The only difference was the amount of sparge water, which was 4.5 gallons after a 1 gallon mashout. That's about 1/2 the amount of water we use for a 10 gallon batch. The Original Gravity was suppose to be 1.091, but it actually came out 13 points shy at 1.078.

I'm not sure why there was such a huge discrepancy between the estimated and measured OG. Could it be the amount of sparge water? Whenever we sparge 20+lbs of grain with 8+ gallons of water our efficiency is usually excellent. How do you guys go about brewing you're 5 gallon batches of high gravity beer? All feedback will be appreciated.

 

[bullinachinashop]

You really answered your own question.
The less sparge water you have to rinse your grains, the less sugar you'll extract from them. You could increase the amount of sparge and boil for longer or you could try to sparge with a different method, but learning what you system will do and adjusting from your notes will help you get to your desired OG.
For this batch, I'd just boil up some DME if you want to get your gravity up.
Good Luck
Bull

 

[y2jrock60]

For this batch, I'd just boil up some DME if you want to get your gravity up.
Good Luck
Bull

Thank you, I never thought about doing that. I figured the issue was due to the lower amount of sparge water. That was really the only variable that changed.

I use DME to make starters, but never added it to my boiling wort. I've used Belgian Candy Syrup before. The guy at the brew store told me to add it with 15 minutes left in the boil. Would I do the same for the DME, or add it at the beginning of the boil? Also, I used about 18lbs of 2-row, how much should I remove from a 20lb recipe to be replaced with DME?

 

[Riseabovebb]

Thank you, I never thought about doing that. I figured the issue was due to the lower amount of sparge water. That was really the only variable that changed.

I use DME to make starters, but never added it to my boiling wort. I've used Belgian Candy Syrup before. The guy at the brew store told me to add it with 15 minutes left in the boil. Would I do the same for the DME, or add it at the beginning of the boil? Also, I used about 18lbs of 2-row, how much should I remove from a 20lb recipe to be replaced with DME?

1LB of Grain is generally equal to .6LBS of DME.

I think what the previous poster was saying is that if you do not hit your gravity reading pre-boil (meaning you achieved less efficiency than the recipe called for), add DME to the boil (with about 15 minutes left) to reach your desired OG.

Here's the math to determine how much DME to add:

DME needed (in lbs) = (Total gravity(target) - Total gravity(from mash))/45 for DME

Ray Daniel's book "Designing Great Beers" covers this in depth in the first few chapters. A worthy read, assuming you haven't already.