title_body: Why is the Dogfish Head 120 minute IPA so expensive?
upvoted_answer: I think there are three main reasons.
  
  1) Direct production costs. Dogfish declares adding hops for two hours, and this has a cost you need to pay (more hops, more time)
  
  2) Alcohol content. Taxes may depend on ABV (for minimum rate of excise duty on beer in the EU, see here). The higher is the ABV, the higher is the tax. 
  
  3) Marketing. The beer is a very special one, and it is easier for Dogfish to find consumers willing to pay more for such a special beer.