Question Regarding Adjusting Recipe for System Efficiency

[Jiffster]

I'm preparing for my next brew and I have a question regarding adjusting the recipe based on my systems efficiency numbers.

I'm still trying to dial in what my systems efficiency really is so I just have to go by what my latest brews have been.

I'm brewing Biermuncher's Black Pearl Porter recipe. In the OP for this recipe, the batch size is 5 gallons.

OG 1.065
IBU 7.5

Since I seem to be getting higher efficiency than what this recipe calls for, when I enter the recipe into Beersmith the estimates are:

OG 1.073
IBU 8.3

Now, I typically like to adjust 5 gal batch recipes to 5.5 gal so I have a bit more into the keg. Should I just go ahead and change the batch size to 5.5 and leave everything else alone?

When I do, my estimated OG and IBU's are:

OG 1.067
IBU 7.9

 

[Redtab78]

I am by far any type of expert, but I think that's what I would do, the only other option is to reduce the gain bill by a little correct? I have been working on my brew house efficiency as well, and what I am finding is for me to hit exact numbers, I have been reducing my bill slightly (usually 1# total but keeping the same % of each grain. My efficieny went through the roof when I ought my own mill, so now for me, I try get start at the exact same line in my keggle with my wort so that I end up with the exact same post boil. Once I got that quantity to be stable (through sparging and draining etc) then the next thing for me to do was to reduce grain bill.

One thing I am still confused about is the efficiency adjustment on beersmith. meaning, if I change my expected effiency in the program, it changes my amounts, but then, I might not hit it exactly, so I adjust stuff on my own....but I may be doing it way wrong, so I am interested in hearing what others have to say on this matter!

 

[dmtaylor]

I find there is a relationship between gravity points and efficiency, such that if you add the two together, it makes almost a constant. Gravity points are just the original gravity with the 1.0 gone, so for a recipe of 1.065, that's 65 gravity points.

What do I mean exactly? Well first you need to know your average original gravity and your average efficiency. If you seem to be getting 78% efficiency all the time and the average batch you brew is 1.062, then your own personal "constant" is 78+62=140. You can remember this number then and use it for any other recipe you want to make. So if you want to make a 1.070 beer, you know your efficiency will drop from your average 78% to about 140-70=70%. It's not exact, but will aim you in the right direction -- maybe you'll actually get 71-72%. But it's close. And the opposite is true as well. Want to make a 1.055 beer? If your "constant" is 140, then you can expect an efficiency closer to 140-55=85%. Probably not quite that much, but you should have no trouble hitting about 82% or whatever. It's pretty close.

So...... you say you're getting higher than typical efficiency. But, is that for big beers, small beers, or typical recipes around 1.055-1.060? That's the key thing to ask yourself. Then you can get a better guess of efficiency using your own personal process "constant". And like I said before, I say "constant" with the quotation marks because it's actually just slightly off, but for most intents and purposes, should get you pretty close.

 

[Jiffster]

I find there is a relationship between gravity points and efficiency, such that if you add the two together, it makes almost a constant. Gravity points are just the original gravity with the 1.0 gone, so for a recipe of 1.065, that's 65 gravity points.

What do I mean exactly? Well first you need to know your average original gravity and your average efficiency. If you seem to be getting 78% efficiency all the time and the average batch you brew is 1.062, then your own personal "constant" is 78+62=140. You can remember this number then and use it for any other recipe you want to make. So if you want to make a 1.070 beer, you know your efficiency will drop from your average 78% to about 140-70=70%. It's not exact, but will aim you in the right direction -- maybe you'll actually get 71-72%. But it's close. And the opposite is true as well. Want to make a 1.055 beer? If your "constant" is 140, then you can expect an efficiency closer to 140-55=85%. Probably not quite that much, but you should have no trouble hitting about 82% or whatever. It's pretty close.

So...... you say you're getting higher than typical efficiency. But, is that for big beers, small beers, or typical recipes around 1.055-1.060? That's the key thing to ask yourself. Then you can get a better guess of efficiency using your own personal process "constant". And like I said before, I say "constant" with the quotation marks because it's actually just slightly off, but for most intents and purposes, should get you pretty close.

So I need to get some more brews under my belt to determine this correct?

 

[dmtaylor]

So I need to get some more brews under my belt to determine this correct?

Yep. After just 2 or 3 batches, you should see a pattern emerging already and then can produce more and more predictable results with each successive batch.

 

[dmtaylor]

SPECIAL NOTE: For recipes that contain added sugars such as lactose and/or maltodextrin, you need to run all calculations assuming none of that in there. What you get with a recipe like that will be non-representative of any "normal" all-malt recipe.

 

[laredo7mm]

Once you get an idea of your system efficiency then you can use BeerSmith to scale the recipe for batch size and efficiency at the same time.

Find the recipe you like >> enter all of the information into BeerSmith just as it was written in the recipe (including their efficiency) >> then use the scaling function to change the batch size and the efficiency to match your system >> BeerSmith will calculate the new numbers.

If the recipe does not list an efficiency, then just input the ingredients and batch size and then adjust the efficiency until you get to the OG that is listed in the recipe. Then do your scaling function to tailor it to your system.

 

[Biscuits]

It is important to know that there are multiple types of efficiencies. IE: "My conversion efficiency is 98% and my Brewhouse efficiency is 75%". I find that my conversion efficiency is generally between 98% and 100% and that my post-boil SG (OG) is 12-15 points higher than my pre-boil SG. So, I if I am shooting for an OG of 1.045, I adjust my grain bill to target a preboil SG of @1.030. It is important to know that any drastic change in the original percentages of the grain bill may change the flavor of the finished product.

 

[dmtaylor]

Great point. When in doubt, insert the word "brewhouse" in front of efficiency every time you see anything from me on the interwebs regarding efficiency.