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160 reviews

The Flex+ is the big brother to the standard Flex. Out of the box, it features an upgraded tri-clamp racking arm, tri-clamp butterfly valve and upgraded high pressure lid and clamp that can handle up to 15psi.

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Estimated Total $415.00
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The Flex+ was designed to be the most versatile, upgradable and longest lasting small batch fermenter on the market. With over 25 accessories (and counting!) you'll never run out of pieces to customize your Flex+ with.

Out of the box, it features an upgraded tri-clamp racking arm, tri-clamp butterfly valve and upgraded high pressure lid and clamp that can handle up to 15psi. The higher-pressure rating allows you to carbonate and ferment in the same vessel. Now, you can carbonate your beer in a little over 24 hours as opposed to seven days!


  • 304 stainless steel; 1.2mm (18ga)
  • All sanitary welded ports (no-weldless fittings)
  • Designed for 2.5 to 6 gallon batches -7 gallon total capacity
  • 15psi working pressure, great for pressure transferring, carbonating, or using as a brite tank.
  • Etched volume markings
  • Fully polished finish
  • 15” wide by 21” tall (to top of 4” TC)

Lid Features:

  • Stainless band clamp for simple lid installation
    • Completely removable lid for easy cleaning
  • 4" TC modular top port
    • Allows for hop additions, temp control coil, top sight glass, etc
  • (3) 1.5" TC ports which allow for:
    • Blow Off Port – Dedicated port for an airlock or blow off tube
    • Hop Port – Dedicated port for adding hops
    • PRV Port – Dedicated port for your pressure relief valve (PRV)

Body Features

  • 1.5” TC racking port with rotating racking arm
  • 1.5” TC secondary port for thermometer, sample valve, etc.

Have more questions?

Head over to our FAQ page for quick answers!


Customer Reviews
4.9 Based on 160 Reviews
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Paul H.
United States

Thoughtful Engineering

Many home brew products modify existing hardware for brewing. Take a spaghetti pot, drill a couple of holes, and add some accessories that don't exactly fit. Everything about Spike Brewing products fits. Every design detail has been thought through and the question of "what is best" is obviously sought-after. I plan on changing out my older equipment and continuing to invest in Spike.

Lance C.
United States United States

Nicest fermenter I’ve owned

Very nice fermenter. Awesome craftsmanship.

Ernest M.
United States United States

Spike Flex Plus Fermenter

Made my first brew using it and it AMAZING. Love the way that I don’t have to use hoses to pour from fermenter to bottles and now I have a way to pressurize my fermenter if I want to do a keg which I did not have that option on my plastic fermenter and it is very easy to clean

United States United States

First Ferment Performed Great

What a GIANT step up from plastic buckets! Right out of the box, this beauty was easy to set up and put to work! I purchased the legs/shelf/casters and may not use them in the future for cleaning purposes. (I will have to completely disassemble to take upstairs to the kitchen sink to clean) However, fermentation was amazing! Performed excellent and easy to sample through the process. Temp control was spot on! (Used heater only as my basement is cool) You won't regret putting your buckets into retirement and upgrading to this!

Connor W.
United States United States

Good but leaky

It was good. Served it’s purpose but the parts you screw together don’t fit perfectly and require some Teflon tape to make a leak proof fot. Also the dip tube doesn’t really hold well unless you use a lot of Teflon tape. Seeing that it sits inside your fermenter, it gets quite yucky. Having to replace it every time I use it causes me to go through more Teflon tape than I would like. Other than the amount of tape, there’s nothing else I have to complain. It seemed to stay sealed and no infections got in. It’s small compact size fits nicely in most spaces and still allows room for the airlock to breathe.

Pressure Capable

The main selling point of the Flex+ over the standard Flex is the ability to pressurize up to 15psi compared to the Flex’s 2psi capabilities. What does this mean? Pressure capable means you can carbonate beer inside your fermenter (as opposed to bottles or kegs) in a little over 24 hours as opposed to a week. You can also pressure transfer your beer directly into a keg or bottles, eliminating any oxygen exposure.


With over 25 accessories available there’s no limit to what this fermenter can do! Want to add a thermometer or sight glass? It has ports for attaching those. Want to add wheels or leg extensions to transfer directly into a keg? It can do that.

Stainless Steel

We all start with glass carboys or plastic buckets, but the day you graduate to stainless is the day brewing gets extra fun. 304 stainless steel is professional grade, easy to clean, scratch resistant and will last a lifetime.

Removable Lid

To remove the lid, simply pop off all five clips around the side. That way, you can get your entire arm in the fermenter to clean and sanitize it.

01 / 06

3-Port Lid

The Flex+ comes standard with the 3-Port Lid. This lid and clamp combo are designed to hold up to 15psi and offers even more “Flex-ability" over the standard Flex. The lid has three 1.5” tri-clamp ports. These ports are specifically designed for a blow off (vents the CO2 gas that is produced during fermentation), hop additions port (so you don’t have to take off the entire lid or remove another accessory on the lid) and a pressure relief valve (PRV port) so you can stay safe when your Flex+ is under pressure.

*The 3-Port Lid will also fit the standard Flex.

02 / 06

Cone Shape

Commerical fermenters are cone shaped to reduce the amount of surface area the beer and dead yeast have to interact with. A flat bottom fermenter spreads yeast out along the entire bottom. A cone shaped fermenter reduces the contact surface area by over 50%.

03 / 06

Temperature Control

We can only brew so many styles of beer at room temperature. The Flex+ has a specially designed temperature control system called the TC-100, which will keep your beer within 1 degree of whatever your target fermentation temperature is!

04 / 06

Racking Arm

Racking is when you move your beer from the fermenter to a serving vessel. The Flex+ has a dedicated racking port, which is the lowest port with a valve. On the inside of the valve, the racking arm can be attached and rotated so you can drain the fermenter without sucking up all the dead yeast and trub that has accumulated in the cone. A racking arm comes standard with all Flex+ orders.

05 / 06

Tri-Clamp Ports

...two of them to be more specific. We added these connections to give you endless “Flex-ability” when you brew. Add a sample valve to pull those delicious samples or a sight glass to watch the clear beer drain out.

06 / 06

Half Batch Capable

The Flex+ can ferment up to 6 gallons of beer, but you don’t have to be committed to that amount every time. The Flex was designed to easily ferment a 2.5 gallon batch as well. Drink as much or as little as you want!

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