October 21, 2005
Top Factors affecting Olive Oil Flavor
1. Quality production and storage methods - The biggest determinant - you must start with good olives - see below
2. Fruit Maturity - a Tuscan and a Spanish olive picked green may produce a more similar oil than a Tuscan olive picked late or early in the season.
3. Olive Variety - UC Davis paper by Paul Vossen
4. Growing Region
5. Seasonal variations in weather and growing conditions
6. Pressing Method - Although much is made of different pressing techniques, if properly done they will produce very similar oils with the same olives.
Top Ten Factors in Producing Quality Olive Oil
By Paul Vossen
1. The Olive Is A Fruit and Should Be Treated As Such - The delicate nature of a ripe fruit needs to be protected from pressure temperature, and abrasion. Breakdown of the fruit begins the fermentation process and the development of defective oils. Affirmation of this premise is essential in producing quality oil.
2. Control Diseases and Pests - Any pest that directly attacks the fruit must be controlled to prevent fruit decay.
3. Harvest and Transport Fruit With Care & Separate Ground Fruit - Do not compromise the integrity of the fruit. Limit the depth of containers to reduce pressure on the fruit. Ground fruit is second class fruit and should be separated from tree fruit.
4. Classify, Separate, & Process Different Classes of Fruit Separately - It is well known that different fruit qualities will produce different qualities of oil. Olive fruit should be separated by ground and tree fruit as well as variety, fruit condition, ripeness, or other sanitary condition. Give priority to the best fruit.
5. Do Not Store the Fruit - Prolonged storage or slow working of the fruit is contrary to the production of quality oil. Oxidation and fermentation occurs in the stored fruit, which can lead to defects and off flavors in the oil.
6. Process the Olives Quickly and at a Moderate Temperature - Quality oil comes from fruit that was worked at temperatures below 86~. This is important for protection of the aromas and reduction of oxidation. Poor quality fruits can be worked at higher temperatures, that at one level can reduce certain undesirable characteristics.
7. Sell Several Grades of Oil - There should be a whole line of oils offered for the consumer at different prices all classified by quality parameters reflecting the source of olives and oils produced.
8. Store the Oil with Care - Good storage is extremely important and will permit the proper aging and conservation of desirable flavor components. It is fundamental to store oil in clean stainless steel at temperatures below 65~F.
9. Keep Everything Clean - The failure to maintain cleanliness is a major factor in reducing oil quality since olive oil can so easily become contaminated. Odors from the fermentation of waste products can get into oils in the processing plant. Clean machinery, floors, and walls will prevent rancid odors that can also contaminate the oil. Cleanliness is especially important in the olive washing machines where the wash water needs to be kept clean at all times.
10. Be an Olive Oil Expert - Know just what it takes to produce, harvest, store and process olives of high quality. Become familiar with the sensory evaluation of olive oil and be able to recognize the major defects that can appear in olive oil. Know your customers, educate them about the different classes of olive oil, and help them enjoy this noble food.