After reading an interesting article by Scott Janish I decided to start pressure fermenting a little earlier than originally planned with this brew. Scott also thinks that pressure inhibits the release of esters and fusel flavours and makes a case for pressure fermenting right from the start, but what’s interesting here is that there’s also a suggestion that some of the hops’ oils are lost along with the CO₂ in unpressurised fermentation. Keeping that hoppy goodness locked in is one of the main goals for me, so I’m wiling to gamble a little with potential loss of mouth-feel and maltiness (which my brews to date have in abundance) in return for a little more hops. I therefore decided to ditch the airlock just 24 hours into primary and fit my new spunding valve instead.

The whole process was very easy; just unscrew the cap with the airlock, fit a freshly sanitised carbonation cap, click on the spunding valve kit. Rather than letting the pressure build naturally and then knock it back, I decided to add CO₂ via the dip tube allowing me to adjust the spunding valve there and then, settling on 10 PSI for now.

I did have some concern about the building Krausen getting into my shiny new valve and briefly toyed with the idea of patching the Fermzilla to a spare keg and then fitting the valve to the keg instead, but I needn’t have worried: within 30 minutes of adding pressure the Krausen has retreated significantly and continues to shrink as I write. I believe this is another expected positive side-effect of pressurised fermentation which allows brewers to get better returns from smaller vessels including Cornelius kegs, since less room is lost to head-space.