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174 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 174 Reviews
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Brian P.
United States United States

Great Stainless Steel Fermentor

I have been contemplating moving up to stainless fermentors for quite some time now and finally pulled the trigger on the Spike Flex, man what a difference. Cleaning and transferring beer is a breeze compared to using glass fermentors.. I brew a lot and will definitely be replacing all of my glass fermentors with either the Flex or Flex+ as my budget allows. Thank you Spike Brewing for making a great product!

Ryan R.
United States United States

An absolute must buy.

I’ve got another brands stainless bucket and while yes the price is significantly higher than it. The overall quality and fit and finish was well worth the cost of entry. If you can only get one fermenter? Get this one. I should have gotten two on that sale. Sigh.

Bruce H.
United States United States

Defiantly a step up!

30 years ago I started homebrewing with a plastic bucket as my fermenter, I moved to glass Carboys, then wide mouth Carboys, but I decided to treat myself this summer with my first Spike purchase. Just finished my first beer in it, and it was so easy to clean. The conical bottom kept the yeast out of my finished beer, and the optional sample port was a good purchase as well. And let's face it... it looks bad a$$. It looks and acts like a professional piece of gear, and I'm looking forward to many years, and beers, using it.

Jason J.
United States United States

Family Heirloom

The quality is outstanding! This will get passed down to my son one day.

Robert S.
United States United States

It's Shiney

It worked great the only time I used it. The only complaint is that the outlet valve it is very heavy and is 1.5" but the pickup tube is .5". I sent it through a .375 hose to the serving keg.That leaves a lot of room for O2 contact if you are trying to do low O2 Brewing. I am planning on buying a .5" valve.


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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