Category Archives: Fermenting

Introducing: Dry Hop Thing

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)

First go with … Dry Hop Bottle Thing?

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…

Trial runs with Bag-Thing™️

Since I started fermenting under pressure with the Fermzilla I’ve been wondering how I can reduce oxygen exposure when using more traditional vessels, including the SS Brewtech mini-bucket I purchased at the same time for experimental batches. It’s got a small spigot at the base for drawing samples / transfer / bottling, but whenever you open it you invariably suck air in via the top, and that’s not ideal.

The guys over at Brulosophy have previously something they called at BrüLoonLock, which is basically a mylar balloon taped to a tube and used in place of an airlock. It’s a great idea since it allows capture of CO2 during fermentation which can then be fed back into the keg when samples are taken or during cold-crashing. I’m not sure why they went for a mylar ballon; could be that there’s no material resistance when filling up, could be that CO2 doesn’t permeate that particular material although, even if it did, I wouldn’t care since oxygen is unlikely to get in while CO2 is leaking out.

Regardless, I don’t have access to a mylar balloon right now, and with us being subject to lockdown 3.0 over here one needs to get creative. So I cut a length of plastic food-saver bag and sealed a section of 3/8″ gas line in at one end using RTV, a cross between silicone sealant and industrial glue.

Anyone seen my colostomy bag?

Using a piece of gas line allows me to slot this into the same bung which the airlock uses, and also opens up various other possibilities like pre-charging it with CO2 using a regular John Guest fitting, or including a T-piece and spunding valve in case I ever forget to remove the Bag-Thing once it’s full.

Speaking of which, I wonder what sort of pressure this will withstand? The bag’s edges are welded together and RTV sticks like the proverbial poo to a blanket, so I reckon this should handle a couple of PSI without too much bother. Finally, purging the bag of oxygen prior to use couldn’t be simpler, and that’s where I reckon I’ve got an advantage over the BrüLoonLock: just fold Bag-Thing in half and shut it in a book.

As I write this the bag is connected to my mini-bucket which is fermenting the second batch of blonde extract, and although fermentation has slowed considerably over the last 2 days there’s still enough going on to slowly fill her up. If this experiment is successful then I might make a bigger version so that I can bottle from the keg without having to top up the CO2 reserve, or I may not bother – any oxygen that’s sucked in via the top might well mix readily with the heavier-than-air ‘CO2 blanket’ sitting on top of the beer, but as I’m drawing from the bottom of the bucket and not swirling the brew around I don’t see how any oxygen exposure would have a chance to spoil any but the very last bottle, which is usually a partial fill that’s consumed early.

It’ll never fly…

FermZilla Arrived

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!!