Efficiency wtf?

[evan5159]

Ok so am a noob to all grain. I have done two all grain brews. I hit my target gravity on both on the dot. I went to go buy my third all grain kit and the guy asked my efficiency. I told him I didn't know and he tried to explain it but it was way over my head. I am just a bricklayer after all. Could someone explain it in plain English please

 

[MalFet]

In a given quantity of grain, there is a fixed amount of sugar. If you got every single molecule of that sugar converted and drained into your brew kettle, you'd have 100% efficiency. More typically, some stays behind. That's either because the starch didn't fully convert, or because some of the sugar stayed behind in the water being absorbed by the grain bed. Nobody gets 100% efficiency under any circumstances, but different configurations will be more or less efficient at extracting those sugars. Virtually everyone is somewhere between 60%-90%, and 70%-80% is most typical.

To figure out your efficiency, you just need to divide your actually extracted sugars by the quantity of sugars contained in your grain bill. If you want to do the math, it's relatively easy to do by hand, though most people use software to do it now.

 

[samc]

Great explanation, not sure if it is plain English.

I'd go with, you have a trowel of mortar and you are laying a brick. If you wind up with most of the mortar staying between the bricks and very little hitting the ground you are pretty efficient. If half of it falls onto the ground, you weren't so efficient.

 

[EBloom97]

Your efficiency is how much sugar you're extracting from your grains as a percentage of the maximum amount extractable. Most of us are around 75-85%. Whatever software you're using has it set as a variable somewhere, so when you plug in the grains you're using it calculates your target gravity for you.

 

[Steelers77]

If you have 10lb of 2-row you would have a potential 370 points of gravity (37 points per pound of malt) or 1.074 (370/5gal) in a 5 gallon batch of beer. If you get an actual hydrometer reading of 1.054 that equals a total of 270 point extracted. Now take the actual hydrometer reading and divide it by the potential 270/370=73%

 

[frailn]

I just started calculating my efficiency a few brews ago and struggled a bit figuring it out. Now, I do this:

1. Take a sample of the wort before the boil starts (after mashing), just enough to take a hydrometer reading.
2. Measure the amount of wort in gallons before boil starts. For example - 6.5 gallons of wort in the boil kettle pre-boil.
3. Cool down the hydrometer sample in the freezer/fridge to 60 degrees
4. Take a hydrometer reading of that pre-boil sample.
5. Plug in the hydrometer reading, grain types and grain amounts in pounds into an online efficiency calculator.

The calculator should will give you your pre-boil efficiency. I just googled "homebrew efficiency calculator" and there are several online calculators that come up.

Basically, I have learned that having a consistent efficiency across multiple brews helps you dial-in your recipes so you know what to expect every time you brew. It should be a constant number across all your brews once you get your process dialed in.

Someone please speak up if I am wrong in any of these steps.

 

[evan5159]

Ok then. My maximum gravity for this brew was 1.050. I took a preboil ready in my vial at 1.04. My post boil was spot on at 1.05. I realize my hop additions had something to do with it but would I divide 1.04/1.05?

 

[frailn]

Ok then. My maximum gravity for this brew was 1.050. I took a preboil ready in my vial at 1.04. My post boil was spot on at 1.05. I realize my hop additions had something to do with it but would I divide 1.04/1.05?

I don't think the math is that easy. The online calculators have preloaded data regarding the amount of sugar that can be extracted for each of the grain types you use. So, if you plug in:

7.5 pounds of american two-row
1.75 pounds of munich malt
.5 pounds Caramel 40
1.04 pre-boil gravity
XX gallons pre-boil wort collected

the online calculator uses pre-loaded data regarding the amount of sugar that can be extracted from each grain type along with your gravity and gallons of collected wort to calculate your efficiency.

I high suggest using that online calculator and plugging in your grain types and amounts to get the final number. Here is one I have used recently:

http://www.brewblogger.net/index.php?page=tools&section=efficiency

 

[evan5159]

Thanks everyone

 

[broadbill]

Ok then. My maximum gravity for this brew was 1.050. I took a preboil ready in my vial at 1.04. My post boil was spot on at 1.05. I realize my hop additions had something to do with it but would I divide 1.04/1.05?

You need to account for volume in these measurements. How did you get the max gravity of 1.050? What volume is that for? Pre-boil or post-boil?

Assuming that your max. gravity of 1.050 for your final, post-boil gravity that would mean you would have had 100% efficiency. Not possible.

As Malfet stated, calculating efficiency is quite easy. Provide your volume and we can walk you through it.

 

[Misplaced_Canuck]

I'll give it a shot at explaining it:

Assume a pound of grain in one gallon of water generates a wort of 1.035. (they all vary to some extent). This is the "potential extraction" (ie: the most sugar you can get from that pound of grain. The rest is fiber and proteins, etc).

If you brew 5.0 gallons, with 5.0 lbs of grain, and you get 1.035 (still at 5.0 gallons), you would have achieved 100% efficiency.

That being said...

If you brew 5.0 gallons, with 5.0 lbs of grain, and you get 1.025 (still at 5.0 gallons), you achieved 71% efficiency (.025 over .035).

The general formula:


Max potential specific gravity (SG) =

pounds of grain X (potential extract of grain - 1.000) X 1000
----------------------------------------------------------
volume of batch


Your efficiency =

Your original gravity - 1.000
------------------------------------
Max potential specific gravity - 1.000


So if you have 10 lbs of grain that get 1.037 potential extract in a 5.0 gallon batch:

Max potential specific gravity =

10 x (1.037 - 1.000)
--------------------
5.0

Max SG = .074 (read as 1.074)

So if your OG (after cooling) is 1.058:

My efficiency =

(1.058 - 1.000)
---------------
(1.074 - 1.000)

= 78%.

M_C

 

[crazyseany]

someone posted this link in another post and I feel if I had it available while trying to do it by hand that I could....

http://www.suebob.com/index.php?opt...in-primer&catid=40:brewing-articles&Itemid=66

 

[jetmac]

Great explanation, not sure if it is plain English.

I'd go with, you have a trowel of mortar and you are laying a brick. If you wind up with most of the mortar staying between the bricks and very little hitting the ground you are pretty efficient. If half of it falls onto the ground, you weren't so efficient.

Or better yet,

You have 100 bricks(sugar) to lay(kettle) in 8 hours. If you lay 100 you will be 100% efficient. If you only lay 70 bricks you will be 70% efficient. No one ever lays 100, you have to have a couple breaks during the day.

 

[evan5159]

Ok why is efficiency important?

 

[broadbill]

Ok why is efficiency important?

Because it allows you to adjust recipes to your AG system. Say I give you a recipe that was made to work on my system where I get 80% efficiency. That recipe is set up so that I will get a predictable gravity from a measured amount of grain, on my system.

If you use the same grain bill but your system has a 70% efficiency, you will come up short on your gravity. You avoid this by knowing your efficiency and correcting the recipe so that you get the same gravity as I do. You correct by adding more grain to account for the difference.

Likewise, if a recipe is calculated for 70% efficiency, and I routinely get 80% on my system, I know I have to scale back the amount of grain I use, or dilute the wort more.

Low efficiency indicates problems with either mashing and/or sparging, but typically anything about 65% is considered good.

 

[crazyseany]

Ok why is efficiency important?

also like in the link I posted he states efficiency=bang for your buck

better eff. = less grain to make same beer

 

[scottland]

Knowing the efficency you get is important so you can accurately predict what your OG will be.

Say you brew a recipe with 10lbs of grain:

-If you get 70% efficency, you'll end up with an OG around 1.048 or so.
-If you get 80% efficency, you'll end up with an OG aorund 1.053 or so.

Which will change your ABV by quite a bit. It could be a 4.8% beer or a 5.5% beer, either way it'll still be beer.

What's important is to know what your efficency usually is. With extract, if you want a 1.060 OG, you just add X amount of extract. Assuming you added the right amount of water, you never miss. With All-grain, you need to what your efficency is so you know how much grain you need to make a 1.060 beer.

Once you know you get, say, 74% usually, you can use a brewing calculator, and it'll predict what your OG will be based on how much grain you use.

 

[broadbill]

also like in the link I posted he states efficiency=bang for your buck

better eff. = less grain to make same beer

While this is true, its also a bit of a fool's errand. An extra pound of base grain is 1-2 bucks yet people worry themselves needlessly that they only get 75% efficiency and their buddy gets 80%.

For a recipe with 12lbs a grain, adjusting from 75 to 80% amounts to a adding just little more than a half-pound of grain.

Worrying about better efficiency may make sense in a commercial brewery, but it really doesn't at the homebrew scale. Having a consistent brewhouse efficiency, on the other hand, is a good thing to have.

 

[GIusedtoBe]

I've been doing AG for years and have never calculated my efficiency. I believe its around what others have said. (70-80%) I'm not really concerned with it because my OG's are generally in the range of the recipe or whatever I'm trying to do. If I'm off a bit I'll add a smidge more grain next time. Certainly not scientific, I'm more on the RDWHAHB end of the spectrum but it works for me.

Alan