Carbonation Stones

Sintered Carbonation Stones are an excellent tool to add carbonation to beer in your brewery cellar tanks. CO2 is steadily absorbed into a liquid solution by diffusion which either happens by maintaining an elevated head pressure over time, or by injecting CO2 into a carbonation stone which dissipates the gas into millions of tiny bubbles that rise through the beer and are absorbed into solution. 

Follow these tips to maintain your carbonation stone in top notch condition: 

• Carefully insert/remove the carbonation stone into the tank to avoid nicking the stone 
• Never store carbonation stones in sanitizer or leave them to soak in cleaning solution for extended periods 
• Always rinse sediment, yeast or beer from the stone immediately after draining tank 
• Flush carbonation stones the same direction as CO2 flow, “push” sediment from sintering 
• Only CIP the same direction as CO2 flow and ONLY with perfectly clean solution 
• Never store carbonation stones in buckets with other fittings, they will get nicked and damaged 
• Don’t use scrub pads on the sintered portion of the stone 
• Don’t touch the sintering with bare hands  

Carbonation Stone Manufacturing: 

The manufacturing process that allows stainless steel to be porous for the gas to flow through is created by a metallurgy technique called sintering. This involves taking a charge of highly purified 316ss powder which is deposited into a die, then a compression ram forms the sintered portion of the stone with high pressure and high heat. The sintered end of the stone is then slowly cooled to temper and then passivated, utilizing nitric acid, to form a corrosive resistant surface layer of chromium oxide to the pores. The porous surface has millions of tiny pores which allows CO2 to diffuse into a cold beer in microscopic bubbles, which greatly increases the surface area for CO2 to absorb into solution in a pressure environment. These pores create a controlled flow typically 2µ for brewery applications, which provide a uniform column of injected dissolved CO2 that flows upwards through the beer and is absorbed into solution with the excess gas adding to the tanks head pressure. 

The end result is a sintered tube which is then TIG welded onto a ferrule, which makes up the carbonation stone. At Cellar Supply our carbonation stones have only tri clamp connections, there are no unsanitary threaded connections contacting beer or wort anywhere within the unit. Our Carbonation stone assemblies include a Cellar Supply gas check valves with the carbonation stone, which allows CO2 to enter the stone without beer flowing back into the CO2 line. This setup is commonly used with a  gas quick connect (male) on each carbonation stone assembly and a another quick connect (female) on the CO2 line, so you can simply “plug” into the carbonation stone with the CO2 hose easily without any chance of beer seeping into the CO2 lines. 

Sizing Guidelines for Carbonation Stones

3bbl to 10bbl tanks	8″ Carbonation Stone
15bbl to 60bbl tanks	12” Carbonation Stone
60bbl and larger tanks	14.5″ Carbonation Stone

Using a carbonation stone

To use a carbonation stone, you first need to determine the wetting pressure. This is the amount of CO2 that is required to begin to bubble under normal operation. Each carbonation stone and CO2 delivery system has a slightly different wetting pressure, so it’s a good idea to know at what point CO2 flow begins.  

There are 2 ways to determine the wetting pressure: 

Bucket Wetting Pressure method: 

1. Put the carb stone assembly into a bucket of water and connect to CO2 

2. Turn on CO2 supply and monitor to see at what pressure bubbles start to flow which is the Breakout Pressure 

3. Add 1psi for each 28” of beer column pressure, and add to the above Breakout Pressure and that’s your starting pressure where bubbles begin to flow inside the tank assuming no head pressure 

Rotameter Pressure Method: (Preferred Method) 

1. Connect the carb stone assembly to the filled tank 

2. Utilize an inline Rotameter connected to the CO2 line 

3. Turn on the CO2 supply and adjust until Rotameter float begins to rise – This is the actual starting pressure where bubbles begin to flow into the tank, regardless of head pressure 

Carbonating Tips

• Be sure the beer is cold as possible and that the tank is sealed 
• Use the Wetting pressure as the baseline and slowly add to the tank pressure at 4-5 liters per/minute 
• Utilize an inline CO2 rotameter to monitor flow rate and maintain positive CO2 flow into solution 
• Monitor head pressure and slowly inject CO2 until desired head pressure is achieved, use carbonation chart to determine temperature/pressure for desired CO2 volume 

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Carbonation Stone Products