Draft System

A draft system is a liquid dispensing system that stores and serves beer, wine, cocktails, cold brew coffee, or kombucha from kegs at controlled pressure and temperature. These systems deliver fresher beverages than bottles or cans because the product stays protected from light and oxygen exposure that cause off-flavors. Restaurants, bars, stadiums, and hotels rely on draft systems to maximize profit margins—draft beer yields more servings per dollar than packaged alternatives.

Types of Draft Systems

Direct draw systems position kegs within five feet of the tap, typically in a refrigerated lowboy directly below the bar. This setup dominates smaller bars and restaurants because it’s affordable, simple to install, and easy to maintain. The beer travels through short lines without additional cooling equipment.

Long draw glycol-cooled systems transport beverages up to 500 feet from a central walk-in cooler to taps in multiple service areas. Glycol power packs circulate coolant at 28-34°F through insulated trunk lines that keep the product cold during the journey. Large venues, stadiums, and multi-room restaurants choose long draw systems to centralize keg storage and serve distant locations from one cooler.

Air-cooled systems use fans and ventilation instead of glycol to maintain temperature in trunk lines. These systems cost less than glycol setups but work only in short-to-medium distances where ambient temperature control is manageable.

Essential Components

Every draft system needs kegs (standard U.S. sizes: half-barrel at 15.5 gallons, quarter-barrel at 7.75 gallons, sixth-barrel at 5.17 gallons), keg couplers that connect gas and beer lines to the keg valve, and gas cylinders (CO2 for beer, nitrogen for wine or cocktails). Gas regulators control pressure, while gas lines deliver pressurized gas to kegs and beer lines carry product to faucets.

The dispensing end includes shanks (connectors that mount faucets through walls or towers), tap handles, and faucets that pour the beverage. Direct draw systems need refrigeration units that hold kegs at 38°F. Long draw systems require glycol power packs and insulated trunk lines.

Most American beers use the Sankey ‘D’ System coupler, which fits 95% of domestic kegs. European beers require different coupler types—S, U, G, or A—so bars serving international brands stock multiple couplers.

System Balance and Maintenance

Proper system balance prevents foamy or flat pours. Balance depends on beer temperature (38°F ideal), applied pressure (typically 10-14 PSI for domestic lagers), line diameter (3/16-inch inside diameter for most direct draw applications), and line length that provides enough restriction to match the pressure. Too much pressure or too-short lines create foam; insufficient pressure produces flat, slow pours.

Draft lines require cleaning every two weeks minimum using alkaline-based cleaners. Bacteria buildup and biofilm form in neglected lines, causing off-flavors and wasting product. Regular maintenance also includes checking gas pressure, inspecting couplers for leaks, and replacing worn faucet seals. Modern POS systems can integrate with draft systems to track keg inventory and monitor pour volumes automatically.

Profitability and Versatility

Draft systems deliver higher profit margins than bottles or cans because operators pay less per ounce and eliminate packaging costs. A half-barrel keg yields approximately 165 12-ounce servings, with less waste than individual containers. The global commercial beer tap system market reached $2.4 billion in 2025 and is projected to hit $3.8 billion by 2035.

Beyond beer, operators now use draft systems for cold brew coffee, nitro coffee, wine, pre-mixed cocktails, and kombucha. These applications require different gas types and pressure settings but use the same fundamental equipment. Bars with draft systems also need bar mats under tap towers to catch drips and an ice well nearby for chilling glassware.