Please note that avocados produce more heat than bananas! Cooling may be slower than is needed when using banana rooms to ripen avocados
Early season avocados may take longer to ripen than middle to late season ones.
Mature green avocados should be shipped at 41-51°F (5 to 10.5°C, pulp temperature). Before ripening begins, the fruit pulp temperature should be raised to 65-68°F (18-20°C). If not using pressurized ripening rooms, air stack the boxes (at least 2″ between boxes) to have proper air circulation. Leave 1½ feet between walls and pallets and at least 6 inches between pallets.
Once the fruit pulp temperatures stabilize, place a CATALYTIC GENERATOR in the room, fill it with Ethy-Gen® II Concentrate. Apply 100 ppm ethylene; exposure time is dependent upon season of harvest, age of fruit, and maturity level at harvest. Use the recommendations below as a guide, and make sure to check avocado firmness (here’s where to find avocado firmness testers: QA Supplies) to know when to stop ethylene application:
- Early season fruit: 36-48+ hours
- Mid-season fruit: 24-36 hours
- Late season fruit: 12-24 hours
To achieve 100 ppm, the generator setting will depend on the size of the ripening room:
- Setting 1 for rooms 1600 – 2500 cubic feet.
- Setting 2 for rooms 2500 – 5000 cubic feet.
- Setting 3 for rooms 5000 – 7500 cubic feet.
- Setting 4 for rooms 7500 – 10000+ cubic feet.
Please note that all rooms vary in terms of how air-tight they are, so if more precise PPM determination is required, air testing for ethylene PPM levels is recommended.
Note: If using a Sure-Ripe® generator, this unit will convert 1 US quart of Ethy-Gen® II to ethylene in approximately 12-14 hours. This will be enough ethylene for 1 ripening cycle depending on the size and condition of the room. DO NOT use any of our generators in rooms of less than 1600 ft3 (45 m3)
Humidity is very important. It should be maintained at 90-95%.
Carbon dioxide will build up during ripening. Anything above 1% may retard ripening or cause “checkerboard” ripening within the room. If automatic ventilation is not in place, be sure to vent approximately every 12 hours by opening the doors for 20 minutes even while applying ethylene.
Check pulp temperature at least twice per day and maintain proper pulp temperature.
The fruit should be ready to ship within 3-6 days depending on the season, pulp temperature and degree of firmness. Ripened fruit may have the stem end button become more pliable indicating the softness process is beginning.
Once ripening has reached the desired degree of firmness, lower the pulp temperature to 40-42°F (4.5 to 5.5°C).
CAUTION: Do not hold mature green, unripened avocados at pulp temperature below 40°F. Chilling injury will occur, and the longer avocados are held at low temperatures, the more severe the injury that will be caused. Chilling causes grayish-brown discoloration of the skin and flesh. If chilled before ripening, the fruit will not ripen properly.Ripened avocados are less susceptible to chill damage; they can be stored as low as 36°F (2°C).
For more information on avocados and other fruits, please visit the web site of UC Davis. A great resource for any Fruit Ripener is a publication from UC Davis entitled “Fruit Ripening & Ethylene Management.”