Efficiency math ?

[tangofoxtrot308]

If my Beersmith efficiency is set at 72 and it says my OG should be 1.040 and I have a OG of 1.027 does that give me apx 71 percent??

I suck at math and got these figures from a online calculator. My first all grain was .052 out of .069 this one is my 2nd. My first using my own mill.

If my calculations are right and I'm at 71 percent I'm happy for now, if not then explain to me how to calculate the rate between a 72 percent OG and what I have? Also what is the speed of light...lol

 

[emjay]

If everything in BeerSmith is truly set up correctly... you're getting 48.6%

27/40 * 72

 

[tangofoxtrot308]

I need to do some looking at Beersmith when I get home but I'm pretty sure it shows efficiency being 72 percent and states my OG being 1.040. I'm assuming by it showing 1.040 as OG it means 72 percent OG...is that correct? Would .040 be 100 percent?

Well if I'm at 48 I'm really sucking at AG

 

[tangofoxtrot308]

Got home and saw signs of activity in my current brew...sweet!

I also played around on beersmith and noticed I needed to change the post boil batch size to go along with my measured OG. Once I did this it jumped on both my AG brews to 69 and 72 respectively. I put the amount of wort I had in the kettle post boil even though it says batch size. Batch size for fermentor is already posted at the top. It was preset to 5gl even though this batch was a 2.5gl tester. Thanks for the advice so far so good I guess. I'm pleased with what I accomplished in my first two AG.

 

[cmoon]

Actually you don't even have to do the math, just change the efficiency in beersmith until it matches what you got.

By the way, it is very likely if you missed your gravity by that large a margin (1.027 instead of 1.040), you've undoubtedly made some huge and rather obvious mistake. For instance, I did something like this recently and realized after the fact I had shorted my grain bill by two lbs of base malt.

 

[onipar]

I used this to calculate efficiency: http://www.brewersfriend.com/brewhouse-efficiency/

I have to agree that if you were expecting a 1.040 OG (calculated with 72% efficiency), and you only got an OG of 1.027, there is a pretty big decrease in your efficiency. You should definitely try to figure out what caused this.

 

[eriktlupus]

calculated efficiency is easy to do just look at the formula in my sig.

 

[AR-Josh]

No one gave the speed of light as requested. 3x10^8 m/s

 

[NattyBrew]

Efficiency isn't too hard of a calculation, but it does take a little bit of math. I am assuming you are measuring your efficiency on a final volume of 5 gallons. Being able to accurately measure volume is a super important component of getting to your efficiency.

First part is to work backwards from your Beer Smith numbers to get to a 100% efficiency:

5 Gallons x 40 Gravity Units = 200 Gravity Units

200 Gravity Units / x Gravity Units = 72% Efficiency

x Gravity Units = 277.77 Gravity Units

That 278 Gravity Units represents the amount of GU's which you would achieve if you got 100% efficiency based on the grain bill that you input into Beer Smith. To get you current efficiency you do the following:

27 Gravity Units x 5 Gallons = 135 GU's

135 GU's / 278 GU's = 48.6% Efficiency

That efficiency isn't the best so like mentioned above, you most likely have a problem in your brewing process. More important than a high efficiency however is a constant efficiency which will result as you refine your brewing process. A lower efficiency simply means that you will need to use more grain/extract in your recipes when you brew. Most people aim for something in the 65-70% range which is were you see a lot of recipes based off of.

If the math I did above doesn't make any sense, just ask. It took me a little while to get the concept of Gravity Units and Brewhouse Efficiency down but its super useful once you get it. Ray Daniels "Designing Great Beers" is my bible for that reason.

Matt

 

[emjay]

That math was totally unnecessary lol... check my reply above.

 

[NattyBrew]

I think it's important, I guess its up to the brewer. Getting back to total Gravity Units is key to remove the factor of volume out of the equation. If you have an efficiency calculation in Beer Smith based off of 5 gallons of finished beer and you are ending up with four gallons you aren't comparing apples to apples anymore and your calcs are going to be off.

Just the way I prefer to do it to make sure I am accurate in my numbers.

Matt

 

[tangofoxtrot308]

Thanks for the advice! Another mistake I caught was the miscalculation of my hydrometer temp adjustment I actually stand at .031 so it's a little better. I will use the math in the future to try and eliminate volume.

 

[tangofoxtrot308]

Reread efficiency in How to brew and also checked the Beersmith math. The numbers are spot on for a perfect world. Beersmith estimates my preboil volume at X and the BG at Y seems simple enough. The problem that's been screwing me up is my pre/post boil volume isn't "X" it's always more, ie bad OG. After I adjusted my batch volume to the post boil my numbers went up to 70%. Hopefully on my third AG I can keep the water measurements on pace with Beersmith and it'll be a lot less confusing. Like Palmer said sugar is a constant it's concentration (gravity) that changes with volume.

 

[NattyBrew]

Exactly. A small change in your brewing volumes can result in a huge difference in your measured efficiency. Knowing total Gravity Units also lets you make those adjustments depending on your brew day. All you need to nail down is your boil off rate and then you can make adjustments, like boiling longer if you undershot your OG, on the fly and not have a miss in gravity ruin your brew day!

John Palmer's book is also a rock solid resource. Happy Brewing.

Matt