IBU values in Recipes

[smithly]

I did some searching in the website and help section but did not find an answer to the following questions. 

Is the stated Alpha Acids on a hop package measured or calculated?

Reason I ask is that rarely does the value in Beersmith hops db match up to what I have purchased. It appears that the IBU values of hops in the recipe are hops database values that, if changed, will affect the calculated IBU's in all recipes stored in Beersmith. 

How can these differences be accounted for in individual recipes if the AA %'s vary?

Thanks,
Lee in Marana, AZ

[BeerSmith]

Lee,
  Hope alphas do vary by season, vendor, etc...so it is best to enter the actual hops alpha when you brew a recipe.  The database represents average values for these varieties.

  Each recipe stores its own copy of all ingredients, so changing your database won't change all the recipes, and conversely setting an alpha for a particular recipe won't change any other recipes.  This was done intentionally so you can capture a recipe as you brewed it.

Cheers!
Brad

[smithly]

Thanks Brad.  I read the help file and it did not indicate that the this was a variable that could be adjusted for an individual recipe.  Perhaps I was looking in the wrong place.

Appreciate the prompt response.  A real confidence builder in your product beyond the excellent interface and comprehensive inclusion of those items important to making us better brewers.   

Lee in Marana, AZ