I used to relish opening my beer fridge a couple days before brew day and smelling that sweet aroma of fresh hops waft out as my packages of hops sat chilling in the fridge.  But after doing some brief research into hop storage, I found that wasn’t a good thing.  Here’s why.

To keep hops from degrading you need to keep them away from oxygen.  You can also slow the degradation rate the colder you store them.  For every 27 degree drop in storage temperature, you cut the degradation rate in half.  Because of this, hop producers recommend you store your hops in the refrigerator or freezer.

Aside from the storage temperature, keeping oxygen out of the packaging is even more effective.  If you can smell the hops when you open your fridge, that means the packaging is not airtight.  And if you can smell hop aromas coming out, you know that oxygen is getting into the packaging.

The typical Local Home Brew Shop (LHBS) takes bulk pellet hop packages and breaks them down into 1 oz. plastic pouches, “seals” them and labels them to sell.  However, Hopunion is one hop supplier that provides a superior package before it even gets to your LHBS.  They package in a light-proof, oxygen-barrier bag, and also evacuate the air and fill the bags with nitrogen before sealing.  So not only do you get a good barrier to prevent new oxygen from coming in, they make sure you don’t start out with any oxygen.

Of course the downside is you don’t get that fresh aroma when you open your fridge, but you can always use your partially-used hops for that purpose like a sort of homebrewer’s potpourri!

There are a lot of things to do before your brew day to ensure you’re prepared and not scrambling around at the last minute.  One of those things is to check the Alpha Acid (AA) % of your hops you’ll be using for bittering.

Most brewers are familiar with the equations, or at least the concept thereof, for how to calculate a beer’s IBU based on the AA of the hops you use and when you add them.  As you geek out more into this topic and research it, you can quickly find your eyes glazing over as people are babbling on about chemistry reactions and throwing around terms you’re pretty sure they don’t even know what they mean.

From the higher technical analysis of those more chemistry-smart than I, here’s the takeaway that seems to be of practical use.  When trying to substitute hops in a recipe, you should get particular about matching the IBU contribution from your bittering hop additions, and for the flavor & aroma additions, try to match the amount/weight.

Since hops have a range of typical AA% from batch to batch, you should always check the AA% of the hop you bought from the Local Home Brew Shop (LHBS) and tweak your recipe with your brewing software to get the proper amount of hops to add to get the IBU contribution your recipe is aiming for.

And more importantly, it’s a good idea to do this a couple days before brew day.  When you find your bittering hop addition that was planned to be 0.7 oz. of 4% AA Hersbrucker, now needs to bump up to 1.4 oz. since the Hersbrucker hops are running at 2% AA from the LHBS, you’re stuck.  Your little 1 oz. packet of hops that previously was going to have some leftovers, now is short and you need to get another one.  Discover that on brew day and you’ll have no option but to short-change your recipe on the fly and see how it turns out.  Sometimes this creates something unexpectedly good.  Other times it results in exactly what you would expect, which is not what you were aiming for when you planned the recipe.