The Fermenter King Gen 3 is a considerable upgrade from the original Fermentasaurus, featuring an innovative dump valve along with lots of useful add-ons to the Unitank loved by thousands of homebrewers worldwide.

The new dump valve is referred to as the Plunger Valve. Compared to the previous Butterfly Dump Valve, it is a simpler, sleeker design that it much easier to dissemble and clean. It is an overall more sanitary dump valve and we believe that it will help brewers brew even better beer than before since sanitation is key to brewing great beer in the first instance.

Much like a bung or sink plug, the Plunger Valve closes off the bottom of the fermenter by being pushed into place from the top. The seal is airtight, ensuring nothing enters or leaves the bottom hole of the tank. Pulling the Plunger Valve opens the bottom of the tank, allowing yeast slurry and vegetal matter to fall through, it's too easy.

Other new features with Fermenter King Gen 3 include cooling coil ports, CIP sprayball insertion, in built thermowells and Tri-Clover fitting compatibility.


The Fermentasaurus is made of bottle-grade PET plastic that is highly crystalline and pressurisable. The following protocols must be addressed to ensure your own safety when handling the tank under pressure.

1. Do not expose the tank to temperatures above 50C (122F) or below -2C (28.5F).

2. Do not apply more than 2.4 bar (35psi) to the tank under any given circumstance.

3. Never connect to an unregulated pressure source.

4. If you connect to an external pressure source; ensure it has an independent pressure release valve (PRV).

5. Use only the RED PRV supplied by MCH Australia PTY LTD on the pressure lid.

6. Do not use the tank under pressure if it has been physically damaged i.e dropped on the ground.

7. The tank is pressure tested at production and is marked with a date for retesting. Pas the marked date, ensure that the tank undergoes a hydrostatic pressure test before further usage under pressure.


1. The first part to install on the Fermenter King Gen 3 is the bottom spigot as this is the foundation for holding every succeeding part in place.

2.Start by securing the Gen 3 Conical Seal onto the bottom face of the spigot.

3. Allow the spigot to fall in from the top of the tank to the bottom hole.

4. Seat the Conical seal between the spigot and the conical surface of the tank.

5. Firmly lock in the spigot to the tank base by screwing on the Gen 3 Spigot Nut.

6. Seat the collection bottle adapter O'Ring.

7. Attach the Collection Bottle Adaptor.

8. Screw in the Collection Bottle to the Collection Bottle Adaptor.

9. Fit the Plunger Valve O'Ring inside the recess at the bottom end of the Plunger Valve.

10. The bottom end of the Plunger Valve sits inside the spigot through the tank with the centre rod and top end standing stable and upright.


1. With the Plunger Valve in place in the bottom assembly: Attach one end of the Silicone Dip Tube onto the Pickup Float then slide the ring of the Pickup Float down the Plunge Valve rod.

2. Snap the C-clip into place on the recess of the Plunger Valve Rod beneath the two black O-rings to limit how high the plunger valve can be lifted during fermentation.


Out of the box, the Fermenter King G3 lid has 4 ports available for us:


  • 2x Ball Lock Posts.
  • The PRV/Dryhop Port.
  • The Central Plunger Valve Port.



1. Start by sealing the Gen 3 Lid O-ring into the bottom recess around the circumference of the lid.

2. Seat the PRV Housing O-ring onto the PRV Housing.

3. Seat the PRV Housing into the PRV Port within the lid.

4. Seat the PRV into the PRV Housing.

5. Place the SS dip tubes with O-ring through the ball lock post ports in the lid.

6. Place a Universal Poppet into each ball lock post.

7. Tighten down the liquid and gas posts to the threaded ball lock post ports on the lid (it does not matter which side you choose to place either post).

8. Slide the top end of the Silicone Dip Tube onto the SS dip tube under the Liquid Ball Lock Post.

9. Align the Central Plunger Valve port of the lid with the Plunger Valve Rod and push the lid through until it is seated firmly into the top mouth of the tank.

10. Screw on the neck ring to firmly hold down the lid assembly.

11. Place the Plunger Valve Handle on top of the Plunger Valve Rod.

12. Use the Allen Key provided to tighten the grub screw in the handle to the Plunger Valve Rod.


1. It is important to check for leaks to ensure that all of the parts are securely in place so that no beer is lost and the vessel can operate safely during fermentation. Please follow the following steps.

2. Remove the collection bottle and push down on the Plunger Valve so that it is firmly settled inside the Spigot.

3. Pressurise the tank to no higher than 20 PSI.

4. Disconnect the gas line and detect for leaks using a spray bottle filled with foaming sanitiser or soapy water around the seals and joins of the top and bottom assemblies.

5. To fix a leak, DEPRESSURISE the tank first before readjusting the fittings.


1. For cleaning, we recommend non-caustic products such as sodium percarbonate on our Atomic 15 ABC (Alkaline Brewery Cleaner) and to make cleaning easier, we recommend our Gen 3 CIP Cleaning Kit that attaches to the inside of your Gen 3 Lid!

2. For sanitising your Fermenter King Gen 3, it is best to go with non-rinse phosphoric acid type sanitisers.

3. Do not use caustic soda or strong acids as they will deteriorate the plastic material of the tank.

4. Do not exceed temperatures above 30C. PET is a soft plastic and will deform at a higher temperature.


Wort should be chilled below 30c prior to transfer to the Fermenter King Gen 3 tank.

After pitching the yeast, close up the tank and ferment with the Plunger Valve OPEN. Leaving the Plunge Valve closed during fermentation could create a pressure differential between the collection bottle and tank potentially causing the Collection bottle to rupture.

To control the Fermenter King Gen 3's internal pressure, we recommend attaching the Keg King Spunding valve to an MFL gas ball lock disconnect and affixing the Spunding valve set up to the gas ball lock post on the Fermenter King G3 lid.

Temperature can be monitored through the thermowell built into the Plunger Valve. Simply insert a temperature control device probe 6mm or under into the thermowell to gauge liquid temperature readings at any height within the fermenting beverage.

During and after fermentation, hops can be added to the fermenter by de-pressurising and utilising the dryhop port for pellet hops. Once added, the tank can be purged and re-pressured with a regulated Co2 source. Dry hopping can also be performed.

When fermentation is complete, bring the temperature of the beverage down to cold crash the yeast and increase beverage clarity, you can remove the Spunding valve and attach a gas line to hold your desired carbonation pressure when the liquid is cold.

To collect yeast, push down on Plunger Valve to seal the tank's bottom port assembly and remove the collection bottle.

If the internal gas pressure of the tank after fermentation was not enough to carbonate your beverage entirely after cold crashing, attach a regulated Co2 source to the gas post to allow the beverage to finish carbonating to your desired carbonation level.


After each fermentation, it is best practice to clean and sanitise the fermenter, then store dry. We recommend pressuring the tank to 10 PSI and storing in a cool room away from sunlight. This ensures that your tank stays free from oxygen and bacteria over a long period of time.


Fermenter King G3 includes a 2inch tri-clover adaptor. The adaptor can be used in place of the collection bottle. Simply screw the threaded end of the adaptor into the bottom of the assembly of the fermenter. Brewers can choose to attach 2inch tri-clover equipment that utilises 2inch tri-clover seals and clamps. PLEASE NOTE HEAVY 2INCH TRI-CLOVER EQUIPMENT CAN DAMAGE THE TANK.


Inserting the cooling coil kit is optional and for this reason, the ports for the cooling coil will need to be manually drilled into the lid. To insert the cooling coils:

  • Drill two 13mm diameter holes through indentations marked on the lid.
  • Protrude the Cooling Coil Posts from the bottom of the Fermenter King G3 lid so that the male threads are facing upwards with the O-rings on the underside.
  • Secure each post by screwing the Cooling Coil Nut onto the male thread.
  • The Cooling Coil connects to the Gen 3 Lid by pushing the ends through the Cooling Coil Posts. Adjust the seating level of the Cooling Coil to finish.


CIP stands for clean in place. Our optional Fermenter King Gen 3 Cleaning Kit includes the following parts to provide brewers with a powerful CIP system for getting their tanks sparkling clean without scrubbing. This kit includes:

  • 3x 13mm x 1/2 BSP Female Hose Barbs
  • 3x Butterfly hose clamps
  • Stainless Steel Sprayball
  • 12w Submersible Pump
  • 1.5m Silicone Tube Hose 12.5mm x 18.5mm
  • Power Cord


1. Remove the Plunge Valve from the lid and tank.

2. Attach the CIP Sprayball head to the underside 1/2 BSP thread under the lid on the Plunger Valve Port.

3. Remove the Collection Bottle and replace it with 13mm barbed fitting.

4. Using the clamps, attach the included tubing to create a loop between the bottom of the fermenter, through the barbs in and out of the provided pump and to the barb at the top of the fermenter lid.

5. Fill the tank with 5L of warm water below 30c and non-rinse sanitiser to recommended dosage.

6. Run the pump to drive the cleaning solution through the sprayball head until no fermentation residue is noticeable on the interior surfaces on the tank.

7. Rinse with clean water.