Another new gizmo in my everlasting quest to cut diluted oxygen (DO) contamination, this is basically a ball valve fitted to the top of the FV with a plastic bottle on top of that. The idea is that you can place the dry hop pellets inside the bottle and purge it with CO2, then fit it to the top of the fermenter around the same time as transferring the wort from the kettle, where it’ll sit ready for oxygen-free deployment via the ball valve. More on that in a moment.
Although the valve had been sourced ages ago I didn’t use it on the last couple of brews because I hadn’t taken the time to find a suitable bottle – after all this has to fit inside the fermentation fridge along with my Fermzilla. When I did finally get my hands on two contenders I had already started fermenting my latest creation, and since it was now too late to remove the ball valve from the FV I had to find a way of fitting the sanitised, purged bottle of hops onto the ball valve without spilling the payload or letting in oxygen. For this reason I chose the larger of my two bottles, because it allowed me to fold it in half and trap the pellets in the bottom while screwing the bottle onto the ball valve. It worked after a fashion, but I’m not convinced that oxygen was eliminated as well as it could have been if I’d planned things properly, and purged the hops with the ball valve already fitted to the bottle right from the start.
The biggest scope for improvement however is the release process itself, because as soon as you open the ball valve a couple of pellets drop through and the rest get jammed. I had hoped to avoid this scenario by allowing the bottle to dry fully after sanitising it, but alas even dry pellets jammed up in the neck of the bottle and necessitated some aggressive agitation. I’m not happy with this arrangement and will see if I can come up with a way to improve things before my next attempt; perhaps a small auger inside the bottle, or a magnet on a stick, or an external vibrator? (oooh-err)
Maybe the answer is to simply crush the hop pellets down before putting them into the bottle so that they flow more readily as powder instead of getting stuck as pellets, but would this affect their potency while waiting to be deployed? Might be one to experiment…
As kegging time looms I’m thinking more and more about how to transfer the partially carbonated Bure Gold from cold-crashed Fermzilla to Cornelius keg without exposing it to oxygen or converting it to foam. Key to both points is keeping the pressure up and doing it slowly, taking care to purge all equipment and lines of oxygen also.
There’s a great idea in this video for using the gas-in posts of both vessels with a connecting line in order to exactly equalise the pressure between both vessels and prevent foaming, but crucially it requires connection to the CO2 cylinder via a T-piece so that the gas line maintains back-pressure, and dropping the pressure in the keg starts the siphoning process. I don’t have a gas T-piece, and expect that were I to simply connect the pressurised keg to the pressurised vessel any drop in pressure would be equalised via the gas line rather than starting the flow of beer.
Blow-Tie to the Rescue!
On to plan B then, and I’m going to use my spunding valve to maintain back-pressure in the keg while slightly increasing the pressure in the Fermzilla using my gas line and regulator. Here’s how that process breaks down in my head:
Purge the 19 litre Corny keg of air by filling it with no-rinse sanitiser and driving that out using CO2. Repeat with secondary 5 litre Mangrove Jacks keg.
Use spare carbonation caps to purge two transfer lines of oxygen; one with a black disconnect at each end, a second one with one black and one grey disconnect.
Connect the Corny keg’s IN post to the Mangrove Jack’s OUT post using the grey-to-black transfer line.
Use the CO2 line on MJ’s IN post to raise the pressure slightly to 12 PSI. Do the same on the Fermzilla, and this time leave the gas connected. Both vessels should now have identical pressure.
Connect Fermzilla OUT post to Corny keg’s OUT post using black-to-black transfer line. Nothing should happed.
Fully close the spunding valve and fit it to MJ’s IN post. Again, nothing should happen.
Slowly open the spunding valve until it starts to hiss slightly. Beer should begin to flow from the Fermzilla to the Corny keg.
Keep an eye on things in case there’s more beer in the FV than the keg can hold. In theory any beer / foam overflow should go to the Mangrove Jack’s keg, giving me a chance to shut off the transfer before it gets into the spunding valve or the pressure gauge, which I’d left attached as a sign of confidence in my approach.
Much Later …
Everything went pretty much as planned, with the only hiccup being my forgetting to switch the gas on as soon as the transfer started, and mildly panicking for 5 seconds when the spunding valve grew silent. In the end it took somewhere around 45 minutes to fill the 19 litre Corny keg to approximately 17 litres before the Fermzilla’s floating dip tube started drawing bubbles at the limit of its tether.
One thing to watch out for next time: as the level of beer drops to the conical section, the float ball may try to snag on the yeasty trub that’s deposited there which can lead to the dip tube sucking air. Easily fixed by flicking the side of the vessel, but could lead to foam in the keg if it’s not caught straight away.
Speaking of which, neither beer nor foam made their way into the secondary keg. Hurrah! I celebrated by drawing off a very hazy last pint from one of the carbonation caps on the side of the collection jar – thankfully the trub-line was just below this point so I got to enjoy a NEIPA-like hop bomb from the dregs beyond the butterfly valve which the dip-tube couldn’t reach. Very nice!
Another new arrival in the brewery this week: the Fermzilla! This plastic Unitank is a good intermediate step on the way to a much more expensive stainless steel version and will allow me to ferment under pressure, transferring straight to a purged keg without any oxygen getting at my precious beer.
I’m going to run it with a kit first and have selected Bure Gold as a kind of testbed. Watch this space!!