title_body: Using Caster Sugar as Primer in Barrell
upvoted_answer: Doing the math out, assuming my liters to US Gallons conversion by Google is accurate, that would come out to around 1.6-1.7 volumes of CO2 in the beer which is on the lower end of carbonation but probably appropriate for many European ale styles.
  
  Think of something like a Bitter or ESB, that's probably where you'll end up.
  
  Caster sugar is just very fine white sugar, so it's probably some form of sucrose...pretty much all of which are interchangeable.  If this is under carbonated for the style you're going for, check out an online carbonation or priming sugar calculator next time and just pitch sugar according to that.
  
  I always liked Northern Brewer's.  It takes beer in gallons since it's a US site but I like that they have a style drop down and list how much of many different types of sugar to use.