This is an 'efficiency' issue...
The brewing software I use is Beersmith and its easy to adjust the efficiency (and determine your efficiency).
how would i calculate my efficiency using the numbers i pulled?
I just ask Beersmith, so can't tell you the calculations. If you don't want to get the brewing software, start by adding a lb or two of grain to your next recipe and see how close you get. But brewing software is a big help to me.
as is, the efficiency always reads 72%. i need it to read more like around 60%. if i plug in 60%, it doesn't add additional grain. any pointers?
so i plan on buying the ingredients for a British Mild this weekend. here's the malt bill..
7 lbs. 2-row
1/2 lb. crystal 60
6 oz crystal 120
.25 lbs Pale Chocolate
2 oz black patent
how much extra should i buy? i'm not understanding the exact math in coming up with how much extra grain to buy
+1 get the grain bill you describe and then buy a 3lb bag of light dme. If necessary you can add some DME to the end of the boil to get your gravity where you want it. Store the unused DME and use for starters or other batches gravity adjustment. Take good notes and you will start to get a better feel for efficiency on your system
We've gone this whole thread without one post explaining the basics of calculating extract efficiency?
Brew software is great and all, but I really think brewers should be able to understand everything that's going on without it. It's nice to have a calculator to do fancy math for you, but without understanding how 2 + 2 gets 4, you're just shooting in the dark.
Keep this link handy:
Malt Yields
Forget Beersmith. Next brew day, sit down with this link and a pad of paper. Write out your malt ingredients. Make a note of your preboil volume. Then take your first malt ingredient, multiply the weight by maximum PPG, then multiply by your efficiency, then divide by your volume. That number is what you should expect to get from that malt ingredient. For an example:
7 lbs. 2-row
1/2 lb. crystal 60
6 oz crystal 120
.25 lbs Pale Chocolate
2 oz black patent
Let's say you're shooting for 7 gallons preboil.
7 lbs 2-row x 38 PPG x 60% efficiency / 7 gallons = 22.8. You should expect 7lbs of 2 row to get you to 1.0228.
.5lb c60 x 34 PPG x 60% / 7g = 1.46. Your half pound of crystal will give you another 1.00146 of extract. 1.0228 + 1.00146 means we're at 1.024
.375lb c120 x 33PPG x .6 / 7g = 1. 1.025
.25lb Pale Choco x 28PPG x .6 / 7g = .5. Still in the 1.025-26 range.
.125lb black patent x 25PPG x .6 / 7g = .25. Let's say we're at 1.026.
When you're done mashing, if you get 60% efficiency and have 7 gallons in your kettle, you should be able to take a hydro reading and be right around 1.026. If you're not, either your volume is off or your efficiency is. Once you know how to calculate this, you can play with the numbers to give you what you want. For example, if you have 7 gallons preboil at 1.026, you have 182 total points of extract (26 points x 7 gallons). So if you expect to have 6 gallons at the end of the boil, you can figure you'll have a 1.030 beer (182 points / 6 gallons). Or, if you end your sparge and realize you have 7 gallons of 1.030 wort, you can figure you actually got 70% efficiency (2row pale x 38PPG x .7 / 7 = 26, which is a four-point bump and will take you from 1.026 to 1.030).
You can also work backwards. Unless you've got a ton of them, forget calculating specialty grains. As you can see from your mild, they contribute a very small percentage of the total extract for a given beer. If you had something like 14.5 lb of pale malt in your IPA recipe (don't have BCS in front of me), JZ's 70% efficiency would get you in the 1.055 range (14.5 x 38 x .7 / 7g). But if you only got 1.040, you had more like 50% efficiency (40 points x 7g gives you 280 extract points, 280 points from 14.5 gallons of grain is about 19 points per pound per gallon, 19 PPG instead of 38 PPG is 50%). Maybe you did slightly worse, because specialty grains contributed a couple points.
Seriously, the next few brew days, leave the software closed. Use a pen and paper and come up with what you should expect from each malt. Once you understand where the numbers come from, you should be able to hit them. And once you can reliably hit your numbers, you can start tweaking to get things where you like them. Maybe you love your process and don't want to change anything to get better efficiency (I think malt conditioning is a PITA): then just add enough base malt to get the gravity where you want it. For your IPA, each pound of 2row you add is going to get you 2.7 points in 7 gallons on your 50% system. If you were 15 points short (1.055-1.040), add 5.5 lbs, and you'll be there. Maybe you'd like to get better efficiency. Then you can start to fall down THAT rabbit hole.
But it all starts with knowing where your extract comes from.
