Beverage dispensing kegs: systems, brands, properties and compatibilities
The draft keg market combines reusable metal systems, single-use PET kegs, kegs with inner bags, formats specific to homebrewing and traditional systems such as cask. This guide compares the main models and brands to understand compatibility, couplers, pressure, logistics, cleaning and use for beer, wine, vermouth, kombucha, cider, mead and other beverages on tap.
What types and models of kegs exist
Beverage dispensing kegs can be reusable metal, single-use PET, kegs with inner bags, Cornelius, cask, DIN Keg or Euro Keg. Brands and systems such as Dolium, Petainer, KeyKeg, PolyKeg, EcoDraft and Cornelius differ in couplers, pressure, logistics, reuse and compatibility.
Quick answer: how keg systems are classified
Keg systems can be grouped into four main families: reusable metal, such as DIN and Euro Keg; single-use PET or plastics, such as Petainer or PolyKeg; kegs with inner bags, such as KeyKeg, EcoDraft or EcoFass; and specific formats, such as Cornelius for homebrewing or cask for traditional service.
Compatibility does not depend only on the keg brand. You must check valve type, coupler, maximum pressure, whether the beverage is in contact with the gas or not, how the line is cleaned and which gas or driving method the manufacturer recommends.
Contents of the technical guide
Quick comparison of keg systems
| System | Type | Usual use | Couplers / connectors | What to check |
|---|---|---|---|---|
| Dolium | Reusable PET depending on model | Beer and distribution with light logistics. | A, D, G, S depending on configuration. | Valve, pressure, actual reusability and current manufacturer recommendations. |
| Petainer | PET one-way | Beer, cider, wine, kombucha, cold brew, cocktails and beverages. | A, D, S or other valves depending on range. | Pressure, beverage, temperature, depressurization, and recycling. |
| KeyKeg | Keg with inner bag | Beer, wine, vermouth, kombucha, cider, mead. | Specific KeyKeg coupler. | Maximum pressure, inner bag, air/gas, depressurizer and line cleaning. |
| PolyKeg | PET one-way; versions with or without bag depending on model | Beer, wine, cider, soft drinks and beverages. | A, S, G, D, M, K depending on model and valve. | Format, valve, barrier, pressure, bag and compatibility with filling. |
| EcoFass / EcoDraft / EcoKeg | Plastic systems with inner bag or container | Beer, cider, wine and sensitive beverages. | Varies depending on the system: A, D, S, or others. | Reuse, disposable bag, compressed air, cleaning and current availability. |
| Cornelius | Reusable stainless steel | Homebrewing, trials, small batches, kombucha, cold brew coffee. | Ball Lock or Pin Lock. | Differentiate gas and liquid, pressure, internal cleaning and seals. |
| DIN Keg / Euro Keg | Reusable stainless steel | Brewing industry, hospitality and professional distribution. | A, D, G, M, L, S, U depending on the valve. | Standard, capacity, valve, return, industrial cleaning and logistics. |
Dolium
Dolium is a plastic keg system designed to reduce weight and improve logistics efficiency compared to the traditional metal keg. Historically it has been presented as a reusable alternative in certain contexts and compatible with common couplers such as A, D, G or S depending on configuration.
Before working with Dolium or similar systems, it’s worth confirming current availability, type of valve, working pressure, reuse conditions, compatibility with the filling line and packaging management.
Petainer
Petainer is a family of one-way PET kegs designed for beer, cider, wine, kombucha, cold brew, cocktails and other beverages. Their appeal lies in weight reduction, non-return logistics and the ability to adapt to different markets or distribution channels.
As with any PET keg, you must check valve, coupler, maximum pressure, temperature, service life, depressurization and container handling after use. It must not be treated like a returnable metal keg.
KeyKeg
KeyKeg is one of the best-known keg systems with an inner bag. The beverage is contained inside a bag and the propellant acts on the space outside that bag, so the pushing gas or air may not come into direct contact with the liquid if the system is used correctly.
This makes it interesting for craft beer, wine, vermouth, kombucha, cider, mead and other beverages where protection against oxidation or contact with gas may be relevant. It requires a specific KeyKeg coupler and compatible accessories.
Do you work with KeyKeg?
Check KeyKeg couplers, depressurisers, cleaning adapters, fittings and compatible tubing to assemble or maintain your dispensing system.
View KeyKeg accessories Check KeyKeg compatibilityPolyKeg
PolyKeg is a single-use PET keg system with different capacities and configurations. Its current ranges include formats such as 12, 16, 20, 24 and 30 litres in some versions, and they can be fitted with different valves depending on the model.
PolyKeg is interesting for lightweight distribution, export and drinks where returning the container is not practical. Before choosing it, you must confirm whether the model has an inner bag or not, which valve it uses, which coupler it needs, maximum pressure and compatibility with the drink.
EcoFass
EcoFass was conceived as a system with a disposable inner bag and reusable body, designed for beer, cider, wine, and other beverages. Its technical logic is to reduce contact between the beverage and the dispense gas, facilitate logistics, and simplify certain container-cleaning tasks.
As with all bag systems, the product line, tap and connectors do need to be cleaned properly. The bag does not eliminate the need for maintenance of the dispensing system.
EcoDraft
EcoDraft was developed as a system with an inner bag to preserve the drink without the liquid being in direct contact with the propellant gas. In the original article it was presented in both one-way and reusable versions, with applications in beer, cider and wine.
EcoKeg
EcoKeg appears as another reusable plastic system or one with an inner container depending on configuration, aimed at reducing weight and logistics. As with other formats of this type, you must verify current availability, maximum pressure, valve type, compatibility with the drink, and the cleaning process or replacement of the inner container.
Cornelius or Corny Keg
The Cornelius is a reusable stainless steel keg with two separate connections: gas and liquid. It is very common in homebrewing, R&D, product testing and small batches. It can be used for beer, kombucha, cider, mead, cold brew, iced coffee or experimental beverages.
It does not connect with type A, D, G or S couplers. It uses Ball Lock or Pin Lock connectors, and you must always distinguish gas-in and liquid-out to avoid assembly errors.
DIN Keg and Euro Keg
DIN Keg and Euro Keg are reusable stainless steel keg formats. DIN kegs are usually narrower and taller; Euro kegs are usually wider and lower. Both are used in professional distribution of beer and other beverages, and can be fitted with different valves depending on the supplier.
In the original article, type A, D, G, M, L, S and U couplers were mentioned for these formats. In practice, you must always confirm the specific keg valve before buying a coupler or preparing an installation.
Compatibility: keg, coupler, gas and cleaning
The compatibility of a keg system is not decided solely by the brand name. To install it correctly you must confirm four blocks: type of container, valve or connector, dispense system, and cleaning conditions.
| Variable | What to ask | Why it matters |
|---|---|---|
| Valve or connector | A, D, G, S, M, L, U, KeyKeg, Ball Lock or Pin Lock? | Define the coupler or connector required. |
| Maximum pressure | What pressure can the container withstand? | Avoid deformation, leaks or unsafe use. |
| Contact with gas | Does the gas touch the drink or is there an inner bag? | It affects oxidation, carbonation and preservation. |
| Beverage | Beer, wine, vermouth, kombucha, cider, coffee or cocktails? | It changes cleaning, materials, pressure and chilling. |
| Cleaning | Is the container reusable or single-use? | Defines whether the container is cleaned or only the line and connectors. |
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View couplers View connectors and fittingsFrequently asked questions about beverage dispensing kegs
What is the difference between KeyKeg and PolyKeg?
KeyKeg is a system known for its inner bag. PolyKeg is a family of single‑use PET kegs with different models, capacities and valves, some with a bag and others without, depending on configuration. You must check the specific technical data sheet.
Is Petainer only suitable for beer?
No. Petainer is also used for cider, wine, kombucha, cold brew, cocktails and other beverages, as long as pressure, temperature, valve and dispensing system are compatible.
Is Cornelius a professional keg?
It is a reusable keg that is very practical for trials, homebrewing and small batches. In hospitality it can be used for specific projects, but it requires clearly defined connectors, cleaning and pressure.
Which coupler do I need for a PET keg?
It depends on the specific valve. It may be A, D, G, S, M, K, KeyKeg or another system. You should not assume compatibility without checking the model.
Can Install Beer help me compare systems?
Yes. Install Beer can help you compare format, coupler, gas, pressure, cooling, line, tap and cleaning for beer, wine, vermouth, kombucha, cider, mead, cold coffee and other drinks on tap.
Technical note: brands and systems may update their ranges, valves, capacities and recommendations. Before buying or installing, it is advisable to always confirm the technical data sheet, maximum pressure, valve, permitted use and manufacturer compatibility.