Fermenter King Junior is a 20L Pressure Fermenter and Keg capable of fermenting up to 18L of wort under pressure. Junior can also be used as a gravity fermenter by attaching a blow off tube or Airlock.
Junior comes from the same tank mould as our King Kegs but utilises the clear PET material of our 35L and 60L Fermenter King Unitanks.

With a crystal clear PET tank, the Fermenter King Junior comes with complete with a pressure lid fitted with a pressure relief valve and stainless steel ball lock gas and liquid posts.

The liquid ball lock post attaches to a silicone diptube that floats internally on a stainless steel float ball so you always pick up a bright beer from the top of the keg. Fermenter King Junior is a great way to ferment fresh wort kits.

It's relatively small size makes fermenting up to 18L of wort simple. Just attach a Spunding Valve onto an MFL type gas disconnect (not supplied) and you'll be able to control the internal pressure of your fermenter. After fermentation, you can carbonate your beer in the Fermenter King Junior, attach it to your tap system or any hand held tap serve directly out of the fermenter.

Alternatively, you can easily transfer carbonated beverages from Fermenter King Junior to kegs, mini kegs and growlers.

This manual will provide users with information regarding the safe operation, handling and maintenance of the Fermenter King Junior.


1. Clean, wash and sanitise the tank at temperatures below 50c (122F). Do not fill the tank with wort or liquid above 50c (122F).

2. Cleaners must be diluted to suitable concentrations before use. If extended contact time is expected, then users must ensure cleaners are chemically compatible with PET, silicone, EPDM, Polypropylene and Stainless Steel.

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

4. NEVER connect to an unregulated pressure source.

5. If you connect an external pressure source; ensure it has an independent pressure release valve (PRV) pre-set to below 2.4 bar (35psi).

6. Use only the RED pressure release valve supplied by Fermenter King on the pressure lid.

7. Do not tamper with the pressure relief valve.

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

9. Do not expose to temperatures below -2c.

10. Keep the tank out of direct sunlight and other sources of UV radiation.

11. The tank is pressure tested at production and is marked with a date for retesting. If it has been used under pressure, then a hydrostatic test must be conducted after every 24 months of use to ensure it is safe for reuse.


1. Clean and sanitise all components prior to assembly.

2. Thread the red pressure release valve into the pressure lid. Screw down firmly.

3. Ensure that the gas and liquid bulkhead fittings are correctly assembled with the post fully tightened onto the pressure lid. Insert the bulkhead fittings into the holes in the pressure lid and tighten the locknuts. O-rings should be located on the top surface of the lid for correct sealing.

4. Lubricate the silicone dip tube with some none-rinse sanitiser and slide one end over the stem of the liquid post bulkhead fitting. Slide the other end of the silicone tube over the floating pickup tube.

5. Lubricate the entire silicone lid seal with some food grade lubricant and fit to the underside of the Gravity lid.

6. Place the pressure lid on the mouth of the Fermenter and ensure that the seal seats correctly.

7. Put a small amount of food grade lubricant on the top outer ring of the cap.

8. Place the top thread ring over the lid and tighten firmly.

ATTENTION: Ensure the ring pull on your PRV is lying out of the way and not against the posts on the lid as this could result in poor connection when attaching disconnects.


Fermenting beverages under pressure provides brewers with the ability to reduce unwanted esters and speed up fermentation times with the capacity to ferment at higher temperatures with fewer off flavours.

To control the tank's internal pressure, brewers will need to attach relevant Spunding Valve to a Stainless Steel MFL type gas disconnect or premium plastic MFL type gas disconnect. Attach the Spunding Valve to the MFL Disconnect, set the adjustable valve to your desired pressure, then attach the disconnect to the gas post of the tank's pressure lid. The gas post is identified by a notch at the base of the post to help differentiate it from the liquid post. Your liquid post should have the silicone dip tube attached to the float ball inside the tank. You are now able to hold pressure within your tank while releasing excess pressure. If your gauge indicates a slightly different pressure than your desired setting, you can easily adjust the valve pressure. We recommend 5 to 10 PSI on ales and 15psi on lagers.

Be careful when releasing pressure on any beer still fermenting under pressure. The headspace of your fermenter will fill with the fermenting beer's Krausen (foam) and could potentially clog your PRV and gas post dip tube.