Smoke Taint in Olives

Olive Trees The staggering destruction of the recent fires in Northern California leaves many us searching for any remnants of optimism this fall. We are grateful that everyone in our Ranch family remains safe, and we continue to be grateful for the courage and stamina of the first responders. Knowing that our team and Ranch have thankfully not been harmed, many people have reached out to us to ask about the possibility of smoke taint among olives. The short answer is: we do not know. We at McEvoy Ranch do not have experience with this amount of smoke and ash pre-harvest. It is truly unprecedented for us. There is also no laboratory test for the olive fruit to determine smoke taint potential as there is for grapes, but we have reached out to our colleagues in Tuscany, Australia, and Sonoma for their advice. For our loyal customers, please know that olives have a much thicker skin than grapes, so they are less susceptible to smoke taint. It’s hard to know in advance if our crop with be affected, but testing oil immediately after the olives have been milled is customary and mandatory to maintain our oil’s Extra Virgin status before it is released into the market. During this testing we will also test for smoke taint. As with the current fires, there are a lot of unknowns but we will maintain our rigorous organic farming methods to make sure that our crop is in the best possible shape when we harvest approximately five weeks from now. For our friends in the farming community, a much more detailed response is below. Grapes are known to be susceptible to smoke taint. Olive fruit, by nature, has a thicker, more waxy epidermis (skin) than grapes. However, the olive fruit does contribute to photosynthesis so may be drawing in impurities as it respires. Whether the smoky compounds make it into the oil vacuoles within the fruit is not known, though it seems unlikely. The potential for smoky defects to transfer into the oil increases during milling. It seems possible that during the milling and malaxation processes, any ash-covered, smoke-damaged fruit may blend with the oil as it emerges from the cell vacuoles. A thorough washing of the fruit may help prevent this from happening so that none of the ash proceeds into the mill or the malaxer. The olive oil itself can be sent to either a lab or a sensory panel for evaluation (both are needed for Extra Virgin status anyway) to detect smoke taint. The laboratory can test for BaP (Benzo(a)pyrene), a compound that results for incomplete combustion or smoke. And an organoleptic assessment can determine if any defective flavors are present in the oil. It is important to harvest the olives either way. Next year’s crop and the overall health of the trees depend upon this year’s crop being removed. If smoke taint is a concern, a small amount of fruit can be harvested, milled, and the oil tested before committing to milling the entire crop. We will update this information as we learn more when our when harvest begins in about five weeks.