Friday, November 8, 2019

Chapman Fermenter - Closed Transfer To Keg

I modified two seven-gallon Chapman UniVessels to support closed beer transfers several weeks ago. I have since used those closed transfer modifications to fill four kegs. In my experience, the entire transfer process was intuitive and easy to integrate into my brewing routine. The Co2 used to push the beer into the keg also prevented any oxygen from getting inside it. It also eliminated the need to lift beer-filled fermenters out of the chest freezer. The benefits of closed transfers will keep oxygen out and help beer stay fresher longer while keeping my back free of pain.

Before attempting to do closed transfers there are a few things you need to have in place. A fermenter that can hold at least three psi of pressure when sealed. A Co2 regulator that can be set to hold three psi of pressure. These two things are also required when fermenting and cold crashing beer in a sealed vessel. The addition of the gas port on the fermenter serves two purposes. It allows Co2 gas produced during fermentation to escape the fermenter. And adding Co2 pressure to the fermenter during cold crashing as the beer volume decreases.

Using 2 To 3 PSI Of Co2 Pressure To Transfer The Beer From Fermenters to kegs.

When fermenting (5.25 gallon/19.8 liter) batches of 1.055 gravity beers at (68F/20C) degrees the krausen remained well below the gas port in the lid. A plugged gas port would cause pressure to build-up and break the seal between the fermenter body and lid. Creating a mess if krausen were to spill out or worse yet damaging the integrity of the fermenter or lid.

The ball valve outlet port is located (1in/2.54cm) from the bottom of the fermenter. The trub layer remained far enough below the bottom of the ball valve port to allow the transfer of clear beer to the waiting kegs. And the removable lid helped make clean up easy enough to do using hot water and a soft cotton cloth.

Krausen Remained Several Inches Below The Lid Throughout Fermentation

Filling the kegs with StarSan purges them of oxygen before coming into contact with beer. Using Co2 pressure to empty the kegs of StarSan assures an oxygen-free beer transfer. To prepare for the transfer after fermentation completes disconnect the blow-off tube from the Co2 gas post on the lid. Then with the regulator set to 3 psi pressure connect the Co2 line to the gas post on the fermenter. To purge oxygen from the beer transfer line, connect one end to the ball valve on the fermenter. Then loosen the connection to the beer line connector on the other end. To prevent trub from getting into the keg, open the ball valve a little until the beer runs clear. Catching any initial trub laden beer in a small container to be discarded. To transfer the beer, tighten the connection to the beer line connector and attach it to the keg beer post. With the ball valve wide open the closed transfer should fill the keg in about fifteen minutes.

Oxygen-Free Closed Transfer Using Co2 Pressure To Move The Beer

Opening the pressure relief valve on the keg will allow Co2 to escape as the beer volume in the keg increases. The beer will continue to flow as long as the fermenter pressure exceeds the pressure in the keg. Closing the pressure relief valve and disconnecting the beer connector completes the transfer. Close the ball valve and disconnect the Co2 connector from the gas post on the fermenter. Then increase the Co2 pressure to fifteen psi and connect it to the keg to seal the lid gasket. The full kegs can then go into a refrigerator to carbonate and condition.

Still Looking Good As New After Fermenting Two Batches 

The fermenters were easy to clean using nothing more than a steady stream of hot water and a soft cotton cloth. A final soaking of hot Powdered Brewery Wash solution made the inside squeaky clean. Followed by a rinse with clean water and a spray of StarSan on the inside they were ready to dry and put away. The lid needed cleaning once the gas ports, thermowell and hole plug installations. Bar Keepers Friend made short work of restoring the outer finish and making it look like new. Both fermenters will continue to look like new for a very long time with minimal effort.

Friday, September 27, 2019

Chapman Fermenter - Closed Transfer Modification

The plastic fermenters in my brew room are nearly ten years old and ready for replacement. They still produce a good quality beer but they're not likely to support closed transfer keg filling. Using Co2 to push beer into a keg under pressure without having to rely on gravity solves two problems. Not having to dead lift fermenters out of a fermentation chamber will eliminate back strain. And pushing beer into a keg using Co2 will keep the beer fresher by preventing oxygen absorption.


Low Pressure Test Of Co2 Closed Transfer To Keg

The ported Chapman seven gallon UniVessel Tank with ball valve best fit my budget and needs for a stainless steel fermenter. They are well made and sturdy enough for use in low-pressure transfers. However, a few modifications will need to be made to their lids. The center hole needs to be blocked to seal the tank. Holes for a gas ball lock and thermowell weldless bulkhead fittings need to be drilled.


Co2 Ball Lock and Thermowell Weldless Bulkhead Fittings

Tool List:
  • A spray can of no-stick cooking oil 
  • 3/16 inch drill bit 
  • 1/4 to 7/8 inch step bit
  • 3/8 inch electric drill
  • Ruler, center punch and hammer
  • Channel-lock pliers or adjustable wrenches

Mark Center Of Hole Location And Dimple With Center Punch and Hammer

Cooking oil is a food-safe lubricant and perfect for drilling holes in stainless steel. It is easy to wipe off with a paper towel and remove with OxiClean.

Before drilling the 3/16 inch pilot hole spray cooking oil on the lid at the location of the hole. Apply downward pressure on the drill while quickly turning the motor on and off. This will prevent the drill bit from overheating and dulling it.


Slowly Drill Pilot Hole In Lid

Next, coat the step bit with cooking oil. And slowly use it to enlarge the pilot hole to a 1/2 inch diameter. Wipe off any excess oil and drill shavings from the lid.


Increase Hole Size From 3/16 To 1/2 Inch Diameter

Then turn the lid over and carefully remove any sharp edges using the step bit. Using a slow drill speed and minimal downward pressure of the drill motor. Care should be taken to remove any sharp burrs without making the hole larger than 1/2 inch in diameter.


Fermenter Lid With Gas Post And Thermowell Installed

With the holes deburred and all cooking oil removed the weldless bulkhead fittings can be installed. By hand start the threaded fittings into the holes in the top of the lid. Use a wrench if needed to thread the fittings all the way into each hole. Screw the lock nuts with washers on from the lid bottom. Snug the lock nuts up to the fittings hand tight. Then use a pair of wrenches to firmly tighten the lock nuts and fittings. Avoid over-tightening the fittings at this point. Squeezing the washers too tight may cause the fittings to leak or damage the washers.


#10 Rubber Stopper With 5/16 Inch Bolt, Nut And Washers

Stainless Steel Hardware List:


  • 2 - 5/16 x 2 inch hex bolts
  • 2 - 5/16 inch fender washers
  • 2 - 5/15 inch flat washers
  • 2 - 5/16 inch hex head nuts


To seal the 1 3/4 inch hole in the center of the lid with a #10 rubber stopper. Drill a 1/4 inch hole down through the center of the stopper. Then thread a 5/16 x 2 inch bolt with a fender, flat and lock washer into the narrow end of the stopper. Push the stopper into the center hole from the top of the lid. Add a fender, flat, lock washer and nut to the bolt end and firmly tighten them together. This will compress and expand the stopper in the hole creating an airtight seal.


Modified 7 Gallon Fermenters In A G&E 7 Cubic Foot Chest Freezer

When fermenting a Kolsch style beer using 1/4 inch inside diameter blowoff tubes connected to the gas posts. The 5.25 gallons of wort inside the 7-gallon fermenters left plenty of headroom for fermentation without fear of clogging the blowoff tubes. When fermenting a heavily hopped beer using a larger diameter blowoff tube is a good idea. Just unscrew the gas posts and clamp 1/2 inch inside diameter silicone tubing to the threaded end of the bulkhead fittings. The larger diameter tubing will further reduce the chance of clogging. But as far as this batch of beer goes primary fermentation is nearly done and everything is working out perfectly.

The maximum pressure rating of the Chapman fermenters is 3 psi. Use care not to exceed 2-3 psi when leak testing or using the fermenter under pressure. Failure to do so can cause the fermenter lid to become disfigured. Other than that as per Steve Chapman "The fermenters hold up just fine for pressure transfers, and many other uses."