Craft brewers continue to use large amounts of hops per barrel of beer brewed. The popularity of styles that require the use of dry hopping practices (e.g. juicy and hazy IPAs) is the primary driver of this trend in hop use. Dry hopping is the term for adding hops to a beer during active fermentation or during maturation in the fermenter. The high demand for these dry hopped beers increases the incidence of brewers performing the dry hopping task, increasing the risk of beer loss and/or worker injury due to the inherent hazards associated with this task.
The hazards of dry hopping can be mitigated through a two-step hazard assessment process: start by understanding the possible hazards associated with each step of the dry hopping procedure, then choose ways to eliminate or control these dangers. Using the information in this article, brewers can begin to develop a safe and successful dry hopping standard operating procedure (SOP) for their facility by raising awareness of general dry hopping hazards, such as pressure and asphyxiating gases, and hazard control strategies, such as proper use of ladders, equipment limitations and basic safety principles.
Dangers of dry hopping
Here is a general list of the dangers of dry hopping. Keep in mind that these risks are exacerbated by rushing and multitasking. Extra time, planning and mindfulness can increase safety in all brewery protocols.
- Flying and falling objects, such as a tri-clamp coin
- Exposure to high levels of carbon dioxide (CO2) or other asphyxiants
- Falling or being knocked down from a ladder or platform
- Clogged pressure relief/vacuum valve (PVRV) which can lead to over pressurization and catastrophic tank failure
- “hop volcano“, an industry term for when beer, hops and CO2 burst violently from a fermenter in the port where hops are added during dry hopping
Control and mitigate the risks of dry hopping
The second step in a risk assessment is to choose ways to first eliminate and then control the identified risks through safe work practices, engineering controls, personal protective equipment and administrative efforts. In the sections below, readers will find important hazard elimination and control strategies to consider when developing their dry hopping SOP.
Safe Work Practices
- Depressurize tank before dry hopping. This should be clearly detailed in the SOP. Always recognize and consider dissolved CO2 volumes in beer.
- Do not stand directly above or over a port when opening and adding hops. Instead, stand to the port side to keep out of the “line of fire”. This will prevent injury from flying equipment. Production personnel should not stand under the port during the dry hopping process.
- Monitor CO2 exposure. Breathe released CO2directly may cause dizziness or loss of consciousness. Use a gas detector, clipped to the shirt of the employee doing the dry hopping, that measures CO2or displacement of oxygen. Know the warning signs of CO2exposure and get fresh air immediately if exposure is confirmed or suspected.
- Slowly add hops instead of all at once. A periodic pause in your hop addition allows the beer to gassify, helping to prevent a hop volcano from forming.
- Plan extra timeto allow for longer than expected dry hopping procedures and to depressurize the fermenter adequately and safely.
- Focus on the task at hand. Be mindful and careful throughout the act of dry hopping. If the scale begins to move, a hop volcano forms, or the CO2detector alarms, calmly walk away from the situation and reassess the dangers. Then modify the plan of the procedure to complete the task safely.
The 4 Ds of Dry Hopping
- Deploy stepladders
- Do not overfill fermenters
- Depressurize container before dry hopping
- Document safe dry hopping procedures in an SOP
- Do not overfill the fermenter . Fermenters are typically designed with 25% to 35% headspace to allow for expansion.
- Create enough space. When adding tanks, make sure there is enough space between the top of the tank and the ceiling so that there is enough room to access the dry hopping port.
- Use the appropriate tool to access the dry hopping port. Use the correct platform, ladder, lift, or technical walkway for dry jumping. An alternative to ladders is a set of escalators that can reach the top of any tank.
- A-frame ladders should never be bent or leaned against the tank. They are designed to be used when locked in the open position and can slip under a person when misused. Check with the ladder manufacturer to ensure proper use.
- Extension ladders and stepladders must be used correctly. The ladder should be higher than the fermenter. With either type of ladder, maintain three points of contact, face the ladder while climbing, and keep your hips between the side rails while working. Do not carry tools or buckets in your hand. Ask a colleague to stabilize the ladder. They can also watch for other hazards and hand out supplies to improve overall job safety.
- For more on ladder safety, see 5 Steps to Prevent Ladder-Related Injuries.
Individual protection equipment
- Always use and wear proper PPE. In general, the PPE required for dry hopping is standard brewery equipment, including but not limited to non-slip boots, gloves, and safety glasses.
- Fall restraints are required if you are dry jumping over a tank.A fall arrest device is not required if the dry jump operator remains on the ladder.
- Display relevant signagearound the brewery, such as “PPE required” and “Authorized personnel only”.
- Perform and document a detailed hazard assessment for dry hopping operation and equipment.
- Write a SOP. Use the specific hazard assessment details in the SOP.
- Train and educate staff. Allow only trained employees to perform dry hopping.
- Stay accountable for security initiatives developed by the company.Both management and staff must remain true to the company’s safety values.