Saturday 7 January 2023

Spike Brewing - All-In-One PRV - Hands on Review

Pressure fermenting has really taken off in recent years within the homebrewing community. With the abundance of affordable and quality pressure capable fermenters, it's a technique that many a brewer is adopting or considering using, particularly given the well known benefits such as the ability to ferment at warmer temperatures, and the suppression of esters and off flavours that are usually generated by yeast when fermenting at these warmer temperatures.

Working with pressure comes with some inherent risk and danger though, which is easy enough to mitigate as long as you're using equipment that is fit for purpose and setup correctly.

Two key pieces of equipment for pressure fermenting are a spunding valve and a pressure relief valve (PRV). The two are essentially safety devices and are typically used in conjunction with one another, with the spunding valve being responsible for regulating the pressure of the carbon dioxide gas created by fermenting yeast that is captured within the headspace of the fermenting vessel. The PRV is then used as a "safety net", to ensure the maximum working pressure of the fermenter is not exceeded in the event of the spunding valve failing or becoming clogged/blocked.

There are some problems and limitations with the array of spunding valves and PRV's available currently on the market though, which lead to Milwaukee based Spike Brewing coming up with a solution to address these shortcomings.

The All-in-One PRV is Spike Brewing's combined spunding valve and PRV - and with a couple of other neat features included as well, it is as the name suggests, an all in one solution for spunding and pressure relief, negating the need for separate components for each of these jobs as described previously.

We were fortunate enough to get our hands on one of the Spike All-in-One PRV's to review, so let's take a closer look at what it's all about.

Opening the box and we've got the PRV body, with the gauge and ball lock gas packed separately and needing to be attached. The ball lock post comes with some spare seals which is a nice inclusion, but the 1.5" tri clamp and gasket/seal required to attach it to your fermenter are not included so need to be purchased separately.

Spike All-in-One PRV box contents

For assembly, Spike recommend wrapping the 1/4" NPT threads of both the gauge and the ball lock gas post with some pipe/teflon tape and tightening with a wrench or spanner to ensure a good seal and leak free operation. We used some blue tape as you can see below and after attaching both components we had zero leaks.

Thread tape around the gas ball lock post prior to installing

Thread tape around the gauge thread prior to installing

You can see straight away the design is made almost entirely of stainless steel, giving it a sturdy look and feel and a nice weight to it. It's compact, looks great, and boasts plenty of well thought out features. 

At the base of the All-in-One PRV we have a standard 1.5" tri-clamp connection meaning it's compatible with any 1.5" tri-clamp ferrule - a common feature on almost all pressure capable fermenter lids, so you can use it on any fermenter lid with a 1.5" opening, not just those made by Spike.

On the front we have a pressure gauge, with a ball lock gas post on the opposing side of the main body with both being connected using a 1/4" NPT thread.

There's an integrated cup for filling with sanitising solution and a drain port for easy drainage/removal of said sanitising solution.

Finally at the top there's an adjustment knob as well as a quick release plunger for quick and easy venting of pressure.

That's a lot to pack into a single unit, and there isn't another PRV or spunding valve currently on the market that boasts all these features. Let's go through them all now in a little more detail.

The Spike All-in-One PRV fully assembled

First we have the large 1.5" opening that is used for coupling the PRV to the fermenter lid. Although 1.5" tri-clamp PRV's are not new, there aren't any that feature the same large diameter port opening where the diaphragm resides as the Spike All-in-One. Spike intentionally made this port and diaphragm as large as possible to all but eliminate the possibility of the port becoming blocked or clogged, or the diaphragm/spring becoming stuck by krausen or hop debris making it's way in there.

Cross section of the Spike All-in-One PRV showing the large opening and diaphragm style design

Clogging is a major risk when looking at some of the spunding valves and PRV's available that feature smaller port openings, but especially on those that utilise spring and poppet designs or connect to the fermenter using ball lock disconnects which also leverage a spring and poppet design.

Under side shot showing the large diameter diaphragm

The nature of spring and poppet designs is that the surface area of the poppet is quite small, meaning they can be easily blocked which is particularly problematic if you have a spring and poppet based spunding valve working in combination with a spring and poppet based PRV. Since both your spunding valve and PRV are typically situated on the lid of the fermenter, if a large krausen were to occur that reaches that high up, then there's a good chance that both could become blocked and result in no way for gas to escape and lead to an excessive and unregulated build up of pressure in the fermenter. Such an event would inevitably be catastrophic for the fermenter.

An example of a 1.5" PRV

1.5" PRV with small opening that can be easily clogged/blocked

The small surface area of poppets results in them having quite a large hysteresis too - meaning the difference in the amount of pressure required to open and then subsequently close the poppet are quite far apart. This in turn results in less accurate regulation of pressure when compared to diaphragm style designs like the Spike All-in-One PRV has.

The large format pressure gauge reading from 0-30psi is also a great inclusion. The large face and crystal clear increments and numbers allow you to accurately determine and set the amount of pressure being controlled by the All-in-One. Many spunding valves have small format gauges built-in which are good for giving an indication that pressure exists but are not known for being easy to read or particularly accurate at measuring exactly how much pressure there is. 

The included pressure gauge is a great size, liquid filled and crystal clear

The Spike gauge is liquid filled too, meaning it's more robust and better able to deal with pressure spikes, humidity and moisture without wearing out the delicate gauge components.

All the other 1.5" PRV's we've seen available don't have an integrated gauge either, meaning a separate gauge needs to be purchased and attached to the fermenter by using an additional 1.5" port on the fermenter or by connecting "T" or "Y" style adapters to allow multiple items to be connected to a single 1.5" opening - adding complexity and cost.

Complexity by adding multiple attachments off single ports is rarely a good idea, especially when you start adding shut off valves into the mix. Inadvertently putting your PRV on the wrong side of a closed valve renders it useless and is a sure way to over pressurise your fermenter.

The integrated ball lock post is a great inclusion

An integrated ball lock gas post is another key feature that allows a gas source to be connected directly to the All-in-One so that pressure can be added back into the fermenter. This is useful if you like to add positive pressure to the fermenter head space at the beginning of fermentation after pitching your yeast, or for performing pressure transfers from your fermenter. Where you would otherwise have to remove your spunding valve if attached to the gas ball lock post before you could connect your gas source, having the gas ball lock post integrated on the PRV negates this and is a simple yet clever idea to make the brewers life that little bit easier and simpler.

Next up we have a reservoir designed for filling with sanitising solution (such as Star San) which means the All-in-One essentially acts like an old-school air lock. As pressure within the fermenter causes the diaphragm to move, gas will escape out through the vent holes and then pass through the sanitising solution to the atmosphere. This creates a bubbling effect giving a crystal clear visual indicator of yeast activity within the fermenter, but also prevents any airborne microbes or other contaminants from entering the fermenter through the vent holes whilst they're open.

There's also a drain hole with a red and black silicone cap over it that can be removed to quickly and easily drain the solution cup without having to disconnect and remove the All-in-One from the fermenter. The diameter of this drain port has been intentionally made quite small so a length of silicone tubing (1/4" or 6mm internal diameter) can be quickly attached to make draining as mess-free as possible. Alternatively you could just stick a glass directly underneath to drain into, but you'd need to be quick and the space between the drain port and the PRV is a little tight. 

The black part of the silicone cap is textured as well, allowing it to be more easily gripped for quick removal without slipping through your finger tips. Little details like this really highlight the level of thought and attention to detail that has gone into engineering this design.

The adjustment knob on the top of the main body is used to adjust the set pressure for the All-in-One. Turning it clockwise will increase the set pressure, and counter-clockwise will reduce the pressure. When fully tightened in the clockwise position, the PRV will vent at 15psi which is the maximum rated working pressure for Spike pressure capable fermenters, as well as many other brand stainless pressure fermenters. 

This maximum pressure setting of 15psi is another reason why this unit is a true "All In One" as it negates the need for a secondary "safety net" PRV like what is required with other spunding valves that can be tightened or fully closed off, which if left unchecked could allow the maximum rated working pressure for any pressure fermenter to be exceeded.

There aren't any graduation markings when adjusting the pressure either to give you an indication of what pressure the All-in-One PRV is currently set at. This is because Spike recommend to using the integrated gauge when calibrating/setting the pressure as it will provide more accurate results.

Spike All-in-One PRV - adjustment knob and quick release plunger

At the very top of the All-in-One we have the quick release plunger which allows for some or all of the pressure within the fermenter to be rapidly purged. This is a great way to quickly ensure your fermenter is safe to open and avoid lids, caps and clamps flying off and causing injury or damage - simply press the plunger prior to undoing anything to be certain the vessel isn't currently pressurised. Depressing the quick release plunger requires minimal force to operate which is great, especially compared to other PRV's that utilise a pull type mechanism where you have to pull against the full force of the spring to open the valve for quickly venting pressure. A word of warning though - make sure the sanitising solution has been removed from the cup prior to depressing the plunger or you'll end up with sanitising solution everywhere, as the plunger opens the same venting ports used during normal operation. As you could imagine, any amount of pressure being rapidly vented through whatever liquid is in the sanitiser cup will result in a lot of spray and mess.

Cleaning is simple too, with only the gauge needing to be removed before the entire PRV unit can be submerged in your cleaner of choice like powdered brewery wash (PBW) and/or sanitising solution. Another huge benefit of the stainless steel construction compared to plastic is it's resilience to withstanding the harsh chemicals sometimes used in breweries, which can often cause discoloration or brittleness in plastic components like with other PRV's or spunding valves.

At approximately 16cm in height, the All-in-One PRV does add a bit of height to the fermenter when attached, so it's worth double checking you've got the vertical clearance if you're using a fermentation chamber or fridge that is tight on space

The Spike All-in-One fitted to our Nano-X Fermenter

Currently retailing on the Spike Website for US$150, it's certainly more expensive than many of the other PRV and spunding valves available on the market. We feel this can be easily justified though, given the premium stainless steel build quality and rich feature list. By the time you bought a standard 1.5" PRV, tee piece(s), gas ball lock post and large faced gauge and put them together with clamps and seals, you'd be unlikely to do it for less than the cost of the Spike All-in-One, and it certainly wouldn't look as nice, or be as compact.

Let's also not forget that you're using your PRV and potentially spunding valve to not only pressure ferment your beer, but also protect the significant financial outlay you've made for a quality pressure capable fermenter to ensure you don't damage it by over-pressurising it.

Unfortunately at the moment Spike only ship to the US and Canada, but we'd strongly encourage anyone interested in their products to reach out to them anyway - we've found them great to deal with and would strongly recommend the All-in-One product to any homebrewer in the market for such a device.

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