BYO > BeerSmith = IBU loss?

[jacksonbrown]

Whenever I plug in a recipe from BYO in to BeerSmith I get a significant drop in calculated IBU's. About 25% fewer. Anyone know why this would be the case? I'm set for full boils, pellet hops, and am using tinset.

 

[ArtVandelay]

Whenever I plug in a recipe from BYO in to BeerSmith I get a significant drop in calculated IBU's. About 25% fewer. Anyone know why this would be the case? I'm set for full boils, pellet hops, and am using tinset.

Did you check to see if AA% of the bittering hops used in the BYO recipe matches up to the that specific hops AA% in Beersmith?

 

[TotemWolf]

+1 on the AA%

Also make sure you're boil volume matches theirs. Make sure the extract/grains are have the same potential as well. All of these will effect your IBU's.

 

[jacksonbrown]

I do change the AA% to match theirs. I'm doing a full 7g boil, which is 100% utilization, so I would imagine that's not it. And when I plug in the grain (I'm AG) my projected OG is usually off by only .001. I'm still stiemied.

 

[JLem]

does BYO use tinseth? Is your batch size set the same?

 

[Yuri_Rage]

BeerSmith will automatically account for a utilization loss when choosing whole hops. Choose pellet hops to eliminate that calculation.

Also, check the algorithm used to calculate IBUs, as JLem suggests. Rager, Tinseth, and Garetz are the options available in BeerSmith. Tinseth is pretty common in homebrewing (it's supposedly very accurate for small batch brewing), but not everyone uses it.

 

[jacksonbrown]

Batch size is the same, and it's set to pellets. I don't know if they use tinseth, but I did try changing my settings to the other two systems and it didn't change that much. The biggest difference was 5 IBU (when I needed 20 to be even). I have no problem adjusting my hops to achieve their numbers, I'm just a bit baffled.

 

[Yuri_Rage]

Don't adjust the recipe so that BeerSmith's IBU output matches BYO's printed figure. Adjust the recipe for AA% alone. If you have identical AA% hops, use the amounts printed.

If you significantly change the ratio of AA% to weight, the recipe will turn out much differently than intended. If your hops differ from the printed recipe in AA%, use AAU calculations to determine the amount by weight that you should add. See this page in How to Brew for an example AAU calculation.

Remember, all IBU algorithms are simply estimates. The only way to get actual IBUs is to have a lab analyze a sample of the finished beer.

 

[jacksonbrown]

Don't adjust the recipe so that BeerSmith's IBU output matches BYO's printed figure. Adjust the recipe for AA% alone. If you have identical AA% hops, use the amounts printed.

If you significantly change the ratio of AA% to weight, the recipe will turn out much differently than intended. If your hops differ from the printed recipe in AA%, use AAU calculations to determine the amount by weight that you should add. See this page in How to Brew for an example AAU calculation.

Remember, all IBU algorithms are simply estimates. The only way to get actual IBUs is to have a lab analyze a sample of the finished beer.

Now that's advice I can understand! Thanks, Yuri.