Seasonal Vintages and the Seasons of IPA

Eno Sarris, November 06, 2013

Take a trip through the leaderboards, and you'll notice that Stone's Enjoy By Imperial Pale Ale is a popular beer, in that it's rated well, as well as the fact that it's all over the leaderboards. Every couple of months a new one comes out, and it pops up on the leaderboard like a new beer.

Should we combine them?

If you go by the idea that the recipe is the most important thing, then you'd argue that all of these beers are just one beer, repeated. The point of the beer is to brew a fresh beer that's the same each time, with the only variation coming from which hops are available at the time. That might seem like a big deal, but you can get strawberries all year long, and Stone doesn't seem to think it's a big deal.

If you go by the idea that a beer should have somewhat stable ratings, you might think we should keep the vintages seperate. Here are the ratings for the different Enjoy Bys that we have in the database.

Name Total
Stone Enjoy By 09.21.12 IPA 3.548087432
Stone Enjoy By 11.09.12 IPA 3.012731481
Stone Enjoy By 12.21.12 IPA 3.407638144
Stone Enjoy By 02.15.13 IPA 3.47664413
Stone Enjoy By 04.01.13 IPA 3.494146547
Stone Enjoy By 04.20.13 IPA 3.39800995
Stone Enjoy By 05.17.13 IPA 3.622973054
Stone Enjoy By 07.04.13 IPA 3.936640123
Stone Enjoy By 08.02.13 IPA 3.987603802
Stone Enjoy By 09.13.13 IPA 3.807278532
Stone Enjoy By 10.25.13 IPA 4.006538219
Stone Enjoy By 11.12.13 IPA 3.95055441
Grand Total 3.648098627

That seems like a big spread. Maybe even on the level of Acme IPA, which was declared The Summer IPA because its ratings were so different from spring to summer. But since we noticed that IPA ratings seemed to rise as the summer progresses, why not take a look at IPAs over time? We're still filling in some gaps in the database, so spring is not our friend. But you can get a sense of the change. First comes January to February, all IPAs:

And now June to November.

You'll notice that IPAS are more popular in the height of summer -- no I don't know what's going on in early August there -- and start to decline at the end of the summer. The baseline in January is much lower than the one in summer, too. Now compare Enjoy By's ratings graphically, over time:

Even with our spring problem, you can see lower ratings for the earlier vintages. So at least some of the changes in Enjoy By's ratings are due to seasonal effects. Some might come from small changes in the hop varieties available to the brewer. Some might come from the gathering energy of hype and good reviews.

In the end, though, it's the same recipe by and large. Seems like it makes sense to combine the vintages, doesn't it?