Perfectly poured draught beer is the result of proper temperature, gas pressure and mixture, and a well-maintained draught beer system. It’s easy to take all the variables for granted when beer is pouring well. But improperly pouring beer can be very frustrating, and can result in loss of sales. This chapter is intended to provide useful troubleshooting steps anyone can follow to solve draught beer dispense problems.

The single most common cause of problems encountered in draught beer dispense systems is temperature control. The first step in solving any dispensing problem is to confirm that the temperature of the keg and the cooler are where they are supposed to be. In air-cooled and glycol-cooled systems, the next step is to check the temperature of the beer being delivered to the faucet, confirming that the air and glycol systems used to maintain proper beer line temperature are working properly. The troubleshooting steps that follow are organized by the type of draught beer system and how the systems are cooled, using air or glycol. Direct-draw systems and long-draw systems cooled by air or glycol each have unique features that are addressed in the troubleshooting steps. Other steps including gas pressure and supply, beer supply, and mechanical issues.

Off Flavors

When fresh and properly dispensed, draught beer tastes the way the brewer intended—clean, flavorful, and enjoyable. Draught beer is susceptible to damage from a host of factors, such as age, heat, and air. But the number one factor affecting the quality of draught beer flavor and aroma is poor hygiene. Improper cleaning of beer system lines and components from the coupler in the cooler to the faucet at the bar can lead to significant changes in beer flavor, all of them unwelcome. Over time, poor beer line hygiene will inevitably result in loss of sales due to customer dissatisfaction, and to replacing beer lines at great expense. Staying ahead of these potentially costly outcomes is key to serving great-tasting draught beer.

This chart lists the most common off flavors that occur due to post-brewery unhygienic conditions and the mishandling of draught products. Beer-spoiling bacteria will ruin a beer’s flavor and aroma, and will inevitably lead to lost repeat business and potential sales. While these microorganisms are not health risks, they will cause bacterial infections in draught systems that are often difficult, if not impossible, to completely remove. By establishing a strict draft beer cleaning program, the occurrence of these off flavors can be prevented.

Pouring Draft Beer

Proper serving of draught beer is intended to have a “controlled” release of carbonation to give a better tasting and sensory experience. The evolution of CO2 gas during pouring builds the foam head and releases desirable flavors and aromas.


  1. Hold glass at a 45º angle, open faucet fully.
  2. Gradually tilt glass upright once beer has reached about the halfway point in the glass.
  3. Pour beer straight down into the glass, working the glass to form a one-inch collar of foam (“head”). This is for visual appeal as well as carbonation release.
  4. Close faucet quickly to avoid wasteful overflow.

Pouring Hygiene

  • In no instance should a faucet nozzle touch the inside of the glass.
    • Nozzles can cause glassware breakage; nozzles can transfer contamination from dried beer to glassware.
  • In no instance should the faucet nozzle become immersed in the consumer’s beer.
    • Nozzles dipped in beer become a breeding ground for microorganisms.
  • Importance of one-inch foam collar:
    • While retailers struggle with customers who demand their beer “filled to the rim,” brewers prefer beer poured with about a one-inch collar of foam (“head”).
    • A one-inch head maximizes retailer profit, as foam is 25% beer. Filling glass to the rim is over-pouring.
    • A proper head on a draught beer delivers the total sensory experience, including the following sensory benefits:
      • Visual appeal of a good pour
      • Aromatic volatiles in beer released
      • Palate-cleansing effect of carbonation enhanced
  • Textural and sensorial qualities of beer better presented to consumer

Free-Flow Pouring

  • Beer pours best from a fully open faucet.
  • To control the faucet during operation, hold the handle firmly at the base.
  • Partially open faucets cause inefficiency and poor quality, namely:
    • Turbulent flow
    • Excessive foaming
    • Waste (inefficiency)

Testing for “Beer-Clean” Glass

Beer poured to a beer-clean glass forms a proper head and creates residual lacing as the beer is consumed. After cleaning, you can test your glasses for beer-clean status using three different techniques: sheeting, the salt test, and lacing. Let’s review each technique.

  1. Sheeting Test: Dip the glass in water. If the glass is clean, water evenly coats the glass when lifted out of the water. If the glass still has an invisible film, water will break up into droplets on the inside surface.
  2. Salt Test: Salt sprinkled on the interior of a wet glass will adhere evenly to the clean surface, but will not adhere to the parts that still contain a greasy film. Poorly cleaned glasses show an uneven distribution of salt.
  3. Lacing Test: Fill the glass with beer. If the glass is clean, foam will adhere to the inside of the glass in parallel rings after each sip, forming a lacing pattern. If not properly cleaned, foam will adhere in a random pattern, or may not adhere at all.

Why Cleaning Matters?

In addition to alcohol and carbon dioxide, finished beer contains proteins, carbohydrates and hundreds of other organic compounds. Yeast and bacteria routinely enter draught systems where they feed on beer and attach to draught lines. Minerals also precipitate from beer, leaving deposits in lines and fixtures.

Within days of installing a brand new draught system, deposits begin to build up on the beer contact surfaces. Without proper cleaning, these deposits soon affect beer flavor and undermine the system’s ability to pour quality beer.

When undertaken using proper solutions and procedures, line cleaning prevents the buildup of organic material and mineral deposits while eliminating flavor-changing microbes. Thus, a well-designed and diligently executed maintenance plan ensures trouble-free draught system operation and fresh, flavorful beer.

As a retailer, you may or may not clean your own draft lines, but you have a vested interest in making sure the cleaning is done properly. Clean lines make for quality draft beer that looks good, tastes great, and pours without waste.

Hop Resin Sticky
Grain Protein Gummy
Yeast & Micro Resistant
Minerals Hard
Bio-film Homogenous Mass

All content has been adapted from the Brewer’s Association Draft Beer quality manual.