Brewing is an ongoing education, even after ten or twenty or more years. At Castle Rock we like to keep note of every lesson we learn along the way, to ensure we’re putting out the best possible beers we can. With this in mind, we’ll be drilling a bit further into the recipes behind some new beers as they drop, so you can learn a bit more about their make-up.
IPA: Citra, Brewing Profile, September 2020
When it comes to our single hop IPA: Citra, like most IPAs it’s about putting the hops front and centre. This one is a little closer to the softer, silkier New England-style of IPA rather than the West Coast. (The latter is characterised by bigger bitterness and a spikier finish.)
Water & Malt
The water profile we used for IPA: Citra is intended to give the beer a full, soft mouthfeel, so it’s treated with salts to achieve a high chloride to sulfate ratio. The higher quantity of chloride in the brewing liquor (water) helps bring the malt through to the fore, whereas sulfate “hardens” the water which can accentuate hop bitterness.
In terms of the malt, the bulk of the grist (overall malt bill) is made up of Propino malt. This gives a very pale appearance, however we also cut in a good ratio of crushed oats, which help give that aforementioned silky mouthfeel.
Both the water and the malt decisions are very much geared towards providing a smooth canvas for the rich, juicy Citra hops to come through and make the beer as easy drinking as possible.
When it comes to the hops, this beer is (evidently) a celebration of Citra, which is one of the world’s favourite hop varieties. It consistently delivers a great bouquet of aromas, from mango and lychee through to grapefruit and lime. There’s also an underlying floralness to the hop (although we prefer the word ‘florality’ and intend to write to the Oxford Dictionary).
IPA: Citra has a hopping rate of around 10g/l (grams per litre). We add a little “hot side” (during the boil) to add bitterness but the majority of the total hop bill is added “cold side” (during or after fermentation). 25kg is added to the fermenter during active fermentation. This provides good circulation and better temperature for the extraction of hop oils, which is where most of the lovely juicy aromatics are. Adding during active fermentation also means that a portion of hop oils can be chemically altered by the yeast into tropical and citrus aroma compounds. Biotransformation, as it’s called, is widely explored in softer, NE-style IPAs.
We then add a further 15kg in our hop torpedo, which is a super-efficient way of extracting all of those hop oils. The torpedo is a pressurised vessel which holds hops, through which the entire beer is recirculated for around six hours to bring out and define the hop aroma.
When it comes to the yeast, for IPA: Citra we used Castle Rock’s long standing house strain, which is a fairly clean yeast (i.e. doesn’t kick off huge amounts of esters and aroma compounds during fermentation) but does help back up the hop aromatics. We do continue however to experiment with yeasts and have a really cool strain ready to go for our next NEIPA.
As with an increasing amount of Castle Rock specials and one-offs, we don’t add any finings to IPA Citra. This means that proteins, polyphenols and some yeast remains in suspension in the finished beer, which helps provide a lovely opaque appearance, and also contributes to that fuller mouthfeel and elevated flavour. Plus, no finings means it’s good for vegans!
Citra is out now in cask and can – look out for it in your favourite pubs and bars (and bug the managers if it’s not on yet) – and don’t forget to check our online shop too, fresh stocks of Citra and Session are now available!