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Introduction
In order to leverage the many benefits of pressure fermenting, a key piece of equipment that is required is a spunding valve. The word "spunding" is German, and translates roughly to "bunging" and essentially means to close up or seal.
A spunding valve will allow you to set and regulate the pressure within your fermentation vessel which can provide benefits like decreased ester production during fermentation, as well as assisting with the carbonation of the finished beer. These are just a couple of benefits, check out our previous article on The Benefits of Pressure Fermenting for more detail on pressure fermenting and the benefits you can reap from it.
We've been using our BlowTie 2 for several years now, so we figured it was time to write a detailed review on our experience with it. The BlowTie 2 features an integrated gauge, for an all-in-one unit that easily displays the current pressure. This negates the need for additional t-pieces or hoses to attach a separate gauge like with the original BlowTie spunding valve which is also still available and features only the valve/diaphragm component without an included gauge.
Construction
The BlowTie 2 is primarily constructed of acetal - a high strength, low friction engineering plastic that provides robustness against general wear and tear as well as the harsh chemicals sometimes used in a brewing environment. The body is bright red in colour, with a yellow adjustment knob. It perhaps looks like something from a McDonalds Happy Meal, and being made of plastic it's very lightweight, but don't let this fool you into thinking it's some kind of low-quality toy - ours has had somewhat of a rough life, having been thrown into boxes and dropped multiple times with barely any marks to show for it.
The overall design of the BlowTie 2 is quite simple, with the yellow adjustment knob screwing into the body on top of a steel spring which regulates the opening/closing pressure for the diaphragm which in turn regulates the pressure required to open it to allow gas to escape. The adjustment knob works exactly how you'd expect - rotate clockwise to make it tighter and increase the spunding pressure, or unwind anticlockwise to reduce spunding pressure. The thread on this is quite fine too, allowing for very finite adjustment to really help dial in the pressure you're after.
Duotight Integration
One of the greatest features of the BlowTie 2 would have to be the duotight fitting integration. Duotight is the dual o-ring push in fitting technology that KegLand use for any product that needs to connect to a beer or gas line - and it makes connecting (and disconnecting) hoses like their EvaBarrier products a breeze. In order to connect your BlowTie 2 spunding valve to your fermenter you'll likely need to attach it to a gas disconnect which can then be fitted to a ball lock post like what is found on most pressure capable fermenters. The duotight inclusion really simplifies this and negates the need for hose/stepless clamps to secure things in place - just plug and play!
On the output end of the BlowTie 2 is another duotight connection. This can be left with nothing connected, or you can use a length of beer/gas line to direct the gas flowing out. One thing we like to do is connect the BlowTie 2 output to a soda bottle using a carbonation cap which acts as a type of 'airlock' so we have a (rudimentary) method of measuring fermentation rigorousness based on the bubbling rate from gas coming out of the spunding valve and through the sanitiser solution left in the aforementioned soda bottle. You can also pressurise kegs using the gas created from fermentation by connecting the gas out from your fermenter to one of the posts in your keg, then having the spunding valve connected to the gas post of your keg like in the photo below.
Integrated Gauge Options
The factory-included gauge is scaled from 0-15psi - a suitable range for most pressure fermentation applications, although you can easily swap this out for a different one if you wish. We'd strongly recommend the mini digital gauge upgrade which we did some time ago for more reliable and accurate readings, compared to the analog gauges which are accurate to within +/- 10% of the gauges display range. You also need to be mindful not to exceed the maximum pressure on whatever gauge is installed or you will potentially damage the gauge. The digital gauges are rated up to 100psi, but the factory fitted 0-15psi could easily be exceeded if you're not careful.
A key part of the design of the BlowTie 2 is the diaphragm that opens and closes to regulate the flow of gas out of the valve. The larger surface area that a diaphragm provides, as opposed to other styles of spunding valves that use poppets with a much smaller surface area allow for a finer hysteresis, or difference in pressure required to open and subsequently close the diaphragm. This ultimately gives greater control over the pressure inside the vessel that the spunding valve is attached to with less fluctuations over the course of fermentation.
Dismantling, Cleaning & Maintenance
The simple design with only a few separate parts means that disassembling the BlowTie 2 for cleaning is a very straightforward process - something we've had to do a couple of times after making sure a keg was filled to the brim and having beer exit through the gas post with the spunding valve connected whilst performing a pressure transfer to a keg.
To disassemble, disconnect any hose/tube connections from both duotight ends by pressing down the locking collar to release. Unscrew the yellow adjustment knob anticlockwise all the way then remove it and the small spring seated underneath it. Finally, remove the gauge by unscrewing the 2 screws and then pull the gauge from the housing. Once the gauge is removed you can then soak the entire housing in brewery wash to clean it.
Orientation & Performance
It's important when connecting the BlowTie 2 that you have it oriented correctly. There's an arrow on the side of the body that indicates the direction gas should flow through the valve. Having it on the wrong way will render it useless and will lead to indefinite pressure build up within the vessel it is attached to, so always double check you have it facing the right direction if disassembling or removing the gas disconnect.
So how does it perform? Flawlessly is how we'd best describe it. We've had zero issues with leaks, and the only minor fault we could think of is the occasional cause of pressure creep where pressure had increased slightly beyond what we initially set it to. But even then we're talking about 1-2psi at the most which in the context of pressure fermenting is almost negligible.
Drawbacks
The only problem with the design of the BlowTie is that it is typically connected using a ball lock disconnect. The poppets on ball lock disconnects are small and easily blocked/clogged, so a particularly high krausen during fermentation could certainly cause a blockage that would prevent gas from escaping the fermenter through the disconnect and into the BlowTie. Pressure fermenters should have a pressure relief valve (PRV) as a fail safe mechanism to prevent dangerously high build up of pressure within the fermenter, but a spunding valve with a 1.5" tri clover connection is less likely to suffer from such blockages. Of course there are ways to mitigate this type of problem like using a transparent fermenter like the FermZilla so you can see what's happening inside the fermenter and keep a close eye on things if the krausen is getting too close to the top lid.
Summary & Conclusion
We'd highly recommend the BlowTie 2 spunding valve to anyone looking to take the dive into pressure fermentation. It's simple to use, light weight, affordable, and has proved to be a reliable piece of equipment for us after years of use on multiple fermentations and fermenters. It's flexible too - allowing you to direct the gas output from the valve into other vessels like the soda bottle air lock we mentioned in the article above, and with a ball lock disconnect it's compatible with any pressure fermenter featuring a ball lock post.
The BlowTie2 is available from the KegLand website at AU$8.99 for the spunding valve on it's own, or AU$15.35 for the kit containing a gas ball lock disconnect and short length of hose/pipe to connect it with.
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