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167 reviews

The most “Flex-ible" fermenter on the market. A huge step up from a standard carboy, the Flex product line is made from 304 stainless steel, so scratches and shattered glass are a thing of the past. 

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Estimated Total $265.00
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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!) available, you'll never run out of fun toys to "bling" out your Flex with. You can use the Flex as a simple bucket fermenter with an airlock or add some accessories.


  • 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
  • 2psi working pressure -Strong seal to keep oxygen and bacteria out -Use for pressure transfers to your keg or bottling bucket
  • Etched volume markings
  • Fully polished finish
  • 15” wide by 21” tall (to top of airlock)

Lid Features:

  • 4" TC modular top port
    • Allows for hop additions, temp control coil, top sight glass, etc
  • Airlock port

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 167 Reviews
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A SPIKE Customer
Todd W.
United States United States

Outstanding fermenter.

I’ve owned my Flex for 3-4 years now. I cannot begin to recall all the batches of beer I’ve made with it. I’ve added the wort chiller that goes in the 4” port on top and I’ve added the new adjustable pressure relief valve. This is, without question, the best investment I’ve made in my home brewery. I encourage you to save your money and buy one. You will not be sorry.

Evan T.
United States United States


I have not used it yet but it looks like it will work well for small batches. Waiting for the 3-port lid to become available.

Abraham W.
United States United States

Outstanding piece of equipment

I purchased the Spike Flex+ as an entry-level homebrewer and have performed two fermentations with it. The tank is solidly built with a great selection of add-ons for customization. Easy to setup, use, and clean.

Joshua C.

Bestest Little Big

The Flex+ is literally the best little big fermenter on the market! I only brew 5 gallon batches. I really did not have an interest in larger conical fermenter. I just really thought they would be much more than I needed. The flex+ give you all of the functionality of the larger unitanks (aside from a dumping port) w/ a muncher smaller footprint and matching price tag. I have 2 and absolutely love them!! R2DDH and Bob Barley are the heart of my fermentation!!

Alan F.
United States United States

where is it?

you keep sending me e-mails but I dont even know how to check on my order


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, too!

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.

Spike Flex | How to Rotate Your Racking Arm

A racking arm is a helpful accessory that allows you to drain your fermenter while leaving hops, trub and other debris in your fermenter resulting in clearer beer!

Spike Flex Fermenter

Bring small batch fermenting to a whole new level! With all sanitary welded, 1.5” tri-clamp fittings and 20+ accessories available, you’ll be able to control temps, carbonate, pressure transfer and more in this 304 stainless steel fermenter.

Spike Flex | How to Rotate Your Racking Arm

Spike Flex | How to Rotate Your Racking Arm

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Spike Flex Fermenter

Spike Flex Fermenter

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01 / 05

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%.

02 / 05

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. The racking arm can be attached and rotated to the inside of the valve 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.

03 / 05

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.

04 / 05

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!

05 / 05

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!

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