Clean-In-Place System for Kegs

Homebrewers who have graduated to kegs generally agree that kegs stand head and shoulders above bottles in convenience and ease of cleaning. But even cleaning kegs can be a pain in the neck. The traditional way uses a lot of water and cleaning agents, because you have to fill the keg nearly to the top to ensure that the cleaning solution comes in contact with the entire keg. Then the cleaning solution must be emptied, the keg well rinsed, and again filled, only this time with sanitizing solution.

That doesn’t get the inner plumbing clean or sanitized, however. For that you have to run cleaning solution and sanitizer through the outflow fitting, using your compressed CO2 to push it out. That often means hauling CO2 canisters around the house to follow the process.

But there’s an easier method.

Professional brewers use a closed system commonly referred to as CIP or clean in place to clean and sanitize their equipment.

The traditional CIP system works like this: Put a little cleaning solution in the bottom of your vessel, seal it, and circulate the solution through the vessel’s built-in spray-head system using an external pump. In the brewery caustic soda is used to clean, followed by a rinse, then sanitizer, each run in closed circuit for 30 to 60 minutes. Of course at home you can use more traditional home-brewery cleaning agents.

The Project

To apply the CIP concept to your homebrewery, you will need a few plumbing fittings and a simple pump. The parts will cost you less than $25, assuming you already have an electric drill.

At first we toyed with the idea of modifying the gas-in tube with some sort of homemade spray head. Then inspiration struck and we decided to turn the keg upside down and connect the soda-out fitting to the outflow of the pump! It was a simple, elegant, and cheap solution to the spray-head problem. The idea is to create a pump system that will circulate fluid in the out tube and out the in tube. It will depend on what type of soda-out dip tube is in your keg. Remember, you need to get full coverage inside the keg. You may need to shorten the dip tube. The CIP flow will be reverse that of normal beer flow. In theory we assumed the cleaning solution should strike the bottom of the keg — turned upside down — and cascade down to the fitting side, where it drains back to the pump through the gas-in fitting.


Putting It Together

1 First, prepare your keg for future CIP cycles. Using a socket wrench, remove the soda-out fitting and the long dip tube. If you use Coca-Cola kegs, which have pin locks, you might need a special socket to remove the fittings. It’s a 13/16-inch spark-plug socket with notches to accommodate the pins. These sell ready made for $15 to $30, depending on the supplier. If you have access to the right tools, it’s possible to make your own.

2 Then carefully and gently bend the tube into a shallow bow shape so that when it is replaced, the dip tube hovers above the center of the keg bottom instead of to one side. This will not adversely affect drawing beer. In fact if you do any fermentation in the keg, this will help to keep sediment out of your glass by raising the level of the out-tube.

3 Reassemble the keg tube when you get the bend right.

4 Assemble your CIP pump. Just about any pump will do, as long as you can connect each end to a soda keg connector fitting. Pumps can be a bit pricey, however, so we built this system using an inexpensive drill-operated utility pump that is available in many hardware and home-improvement stores.

Cleaning agents can be hazardous, especially caustic solutions. Make sure your pump is not too big and does not create too much pressure, thus causing a burned hose or a loose fitting. Always wear eye protection.The drill pump is made with male 3/4-inch garden hose threads on each side. To make your connections you will need two 3/4-inch female by 3/8-inch male flare brass fittings. To this fitting attach 3/8-inch female flare to 1/4-inch barb fittings. Then slip beverage tubing onto the barb end and clamp with small hose clamps. You can now attach two lengths of beverage tubing to the pump using the garden-hose fittings.

5 Next, attach your soda keg connectors to the opposite ends of the beverage tubing. Connect the beer-out fitting to the pump’s outflow side. Connect the gas-in fitting to the inflow side of the pump. If you use standard soda fittings, you will need 1/4-inch barb by 1/4-inch female flares to convert them to hose-barb connectors. If you use hose-barb soda connectors, you will not need these fittings.

6 Finally, you need to build a stand to keep the keg hose fittings off the floor.

Make a simple square of wood two by fours, nailed or screwed together. The square should be eight inches or so, depending on the diameter of your kegs. The idea is to get the upside-down keg off the ground, with room for the fittings.


In Use

To test the system we dumped about a pound of dextrose in an empty keg, then shook and rolled it until the sugar dusted the entire inside of the keg. We figured if the system missed a spot, we would see remnants of sugar clinging to the missed places. After running the system with plain water for less than a minute, all the sugar was washed away. There were no dry spots.

To use the system, mix about a gallon of your favorite cleaning detergent solution in the keg. You can use C-brite, B-brite, sudsy ammonia, or automatic dishwasher detergent. Seal the top, put the keg upside down on the stand, then start the pump and let it run for 20 to 30 minutes. You’ll need to put something heavy on top of the drill to keep it from spinning, unless you plan to hold it the whole time.

Give the keg a rinse, then add a gallon of iodine sanitizer mix and run the system again for 20 to 30 minutes (five minutes would do it, if you were in a hurry). You’re done. All the internal plumbing gets the treatment and you only use a gallon of solution for each step. You can even reuse the cleaners and sanitizers for subsequent kegs and carboys.

Clean Carboys, Too!

To adapt the system for a carboy, buy a two-hole plastic carboy cap from your homebrew supplier. Shove a racking cane in one hole — that will be your CIP-in. Then connect the inflow side of the pump to the other hole, using a 1/4-inch by 1/4-inch barbed splicer. You should use hose clamps all around to prevent leaks and one big hose clamp around the plastic cap to prevent it from coming off when the carboy is upside down.

You might also need another two-by-four stand of the same dimensions as the first. Stack the two to create a single deeper stand that can accommodate the carboy.

Improvise. Use your imagination. Have fun while you save on water and chemicals!