Hop Alpha rating question

As I was looking through the small hops selection tonight at my LHBS I noticed most of the hops alpha ratings were different then my notes and then even different then the chart at the store. Is this normal for the these alpha ratings to sometimes not even be close to what beer smith says they are or what even the chart in the store says they are? I assume they are all based on a guidline. Do I keep adding hops in a BeerSmith recipe to match the IBU style if the package I bought was lower then then what it was expecting? Thanks for any thoughts.

They do vary from harvest to harvest, that is why they are listed on the package. What I do in Beersmith is to see what the desired IBUs are for a given recipe (using the AA% already listed) and then in the inventory area change the hops to what I have available. I then adjust my hops to match the IBUs desired. Usually, it's really a negligible amount. I mean, the different between 6.9% and 7.2% doesn't matter to me a bit. One time, though, I was expecting 4.8% tettnanger, and got something like 2.2% and ended up not having enough hops!

Usually, the "high" AAU hops are within a percent or two. I adjust them to get the desired IBUs. The lower AAU hops are usually (but not always) for flavoring and aroma, so I don't really worry about those.

OK that makes sense. The biggest differences that were concerning me is bittering hops I needed to find substitutions for. So after looking up good substitutes I realized that the alpha percentage was quite a bit lower than the original hop in the recipe and then even lower by a bit for what BeerSmith was saying. So I guess I'm on the right track with adding hops in BeerSmith to get them where I need them. If any of that makes sense..

Sounds like my Horizon 13% problem. I was able to find them but for a while I was looking for a substitute. Then I started learning about cohumulone and how Horizon has a very low % (16 - 19%)MEANING that the more of the 13% bittering agents gets isomerized (put into the water).

Yea - it gets deep! So now I look at cohumulone also.

For instance - AHS says to substitute Magnum for Horizon but Magnum has a cohumulone of 24 - 25% of alpha acids. Meaning that IF (for instance) Magnum had a alpha rating of 13% less of the bittering agents would enter the water.

At least that is MY take on it.

Grinder12000 said:

Yea - it gets deep! So now I look at cohumulone also.

Click to expand...

Whew...I haven't gotten that deep yet but I can tell with this passion I will be very soon..