Hands on Review: Spike Brewing Flex Fermentor

spike brewing flex fermenter review

This review is by Homebrew Finds Contributor Brad Probert.  Brad is an engineer, expert homebrewer and experienced reviewer.  Grab a link to Brad’s website at the end of this review.

Spike Flex Stainless Fermentor

Hands on Review: Spike Brewing Equipment Flex Fermentor

Stainless steel is highly valued in homebrewing because of its durability and ease of cleaning. When used in fermentors, this ease of cleaning means you don’t spend as much time scrubbing yeast crust and dry hop debris off the walls of your vessel when done fermenting. And since your beer spends so much time in contact with the surface of your fermentor, it’s easy for aromas to leech in over time to plastic fermentors. Glass of course doesn’t have this problem, but it does have the problem of shattering if you drop it…

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Spike is well-known for their heavy duty stainless kettles and free-standing conical fermentors. With all that stainless laying around in their shop, it’s no surprise that they’re now entering the category of “stainless bucket fermentors”. These bucket fermentors are smaller in size than the long-legged conical fermentors. What’s surprising to me is the price difference between the stainless bucket fermentors and taller conical fermentors. Even with the same holding capacity, you’re paying a few hundred dollars extra just to get a conical fermentor up on stilts. The stainless buckets offer essentially the same features, they just require you to crouch down- which to me, is an acceptable compromise.

Weld Flange from the Outside
TC Flange Seamless Surface in Contact with Beer

Spike’s new Flex fermentor is a bucket fermentor (crouching required) that has a 7.5 gallon volume, and has a 45-degree angle cone on the bottom. Utilizing the same 1.5” TC flanges that they’ve mastered the welding with their Spike+ kettles, you can interchange pieces from the Spike accessory catalog for a thermowell and a draining valve. It comes with a rack arm when time to drain that can be rotated by loosening the 1.5” TC clamp slightly and turning it. That feature is designed for those that want to take advantage of avoiding the fallen yeast that has collected in the 45-degree cone, but want to rotate the arm while draining to try to get as much viable beer out of it as possible. And the racking arm has a simple but ingenious bump welded onto it so you know which direction the pickup tube is pointing while you’re trying to rotate it from the outside .

Polished Interior with Etched Volume MarkPickup Tube Rotated Down into Cone

The fermentor walls are ultra-polished. While this has a super-glam aspect that’s sure to dazzle your friends, it serves a practical purpose as well. The polishing process eliminates any kind of surface roughness, which makes it even easier to clean. The inside of the vessel contains electrically etched black volume markings every 0.5 gallons, the same as they have on their kettles. The base is supported by 3 sturdy legs with rubber caps on them to keep it from sliding around on floors (or scratching your floor).

Lid Clamped on with Seal Visible

The lid looks like something from a 1920s diving helmet. In the middle of the lid, there’s a giant 4” TC port that holds a polished clear hard plastic window so you can easily see what’s going on inside your fermentor without having to open the lid. The base Flex model has a hole for a rubber stopper and airlock, and 5 latches that hook over the edge of the lid and onto a flange on the base. This base latch and seal set-up is capable of holding 2 psi of internal pressure. The Flex+ model uses a band clamp that goes around the circumference of the lid and tightens down with a screw/nut feature. And the hole for the bung/airlock is replaced by another 1.5” TC port. This ups the pressure holding capability of the unit to 15 psi.

With its short & stout size, the Flex can fit in shorter areas, but it is pretty wide. From the bottom to the top of a 3-piece airlock, it stands 22” tall. The widest diameter, with the stackup of the racking arm and a Spike butterfly valve with a camlock fitting at the end of it, is 21” across. If those dimensions don’t work for your fermentation chamber, Spike also has a version of its TC-100 temperature control system available that makes use of some common components from their unitank conicals and a form-fitted neoprene jacket sized to the Flex dimensions.

Hands on Review

The most notable thing when I unpacked the Flex is the shine from its polished surface. It was actually hard to photograph because of the shine and reflections blended all of the surfaces together. The quality of the TC fittings was superb and everywhere the beer would come in contact, was seamlessly smooth. The weld stitching on the outside of the fittings was also top-notch.

The lid seal was thick and burly, making a robust seal to keep carbonation pressure contained. And unlike other latched lids, having five clips instead of four means less distance between clamps and thus more even clamping of the seal.

When it came to cleaning, the polished surface was outstanding. Blasting hot water with my commercial sink sprayer was all that was required to get it back to spotlessly clean after a fermentation. The TC fittings for the thermowell and drain port came off easily to ensure no hidden pockets to hold remnants from one fermentation to another. And a great aspect with all bucket fermentors is the giant lid opening. No special brush or fancy CIP ball sprayer required to get everything out. I’m not a yeast harvester, but with the cone collection at the bottom and wide open lid, I imagine this would make for easy scooping.

The one limitation of the fermentor is the handles. Etched onto them it says “Do not lift when full”. But during the process from boil kettle to keg, I move the fermentor around several times “when full”. Warning aside, I used the handles anyway and didn’t have any issues. They didn’t feel super robust with the weight of 5.5 gallons of beer in it, but didn’t feel like they were going to break on me, so I just paid attention when moving it around.


Overall, the Spike Flex is a great entry to the stainless bucket fermentor category. I like stainless bucket fermentors because of how easy they are to clean afterwards compared to other options. And Spike takes this to a whole new level with the super-polished surface inside that doesn’t let crud bond to the walls. And use of their superior Tri-Clamp weld fittings eliminate secret holding pockets for undesirable fermentation products to stow away from one batch to another. I would prefer more robust handles for moving my fermentor around full of wort/beer, but they seem like they’ll do the job as long as I don’t abuse them.

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More Photos

With Brewer’s Hardware’s Tri-Clover Sample Port InstalledHands on ReviewTight, But if Fits in Full Size Side-by-Side FridgeGravity Fed Keg Transfer5-Clamp Lid with Clear Viewing WindowPost Fermentation with Hot Water Spray Only- SpotlessRacking Arm Designed to Reach Down into Cone

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By Brad Probert.  Check out Brad’s website – beersnobby.com

Special Thanks to Spike Brewing Equipment for providing the unit used for evaluation in this review.

Price, promotions and availability can change quickly. Check the product page for current price, description and availability.

Make sure the components you use are compatible and rated for your intended application.  Contact manufacturer with questions about suitability or a specific application.  Always read and follow manufacturer directions. review:spikeflex tag:tpr rs:6

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