Yup, I can fully appreciate that you might want to avoid drama; still, from the perspective of a consumer, it’s a lot more informative and useful to me to be able to see what specific brands did consistently well, and which poorly or poorly on some variables that are esp important to him or her (eg, I care less about organoleptics than peroxides and polyphenols). A regional analysis can help to guide one, and if we’re lucky push the Europeans to clean up their act, but it matters a lot to me that one of the California brands had polyphenol counts only in the 100-110 range, and another (with ‘virgin’ sensory rating for one bottle) was consistently in the high 300s.

On the variability: how much of this do you think might be explained by things like store turnover and packaging, rather than originating with the producer? Some brands have totally opaque lot numbers rather than proper expiry dates, and the oils at one store could have been sitting out in the store’s shelf, in the light (maybe even sunlight) for 2 y, while the product at another could be from the latest season and have just been taken out of a crate. Also, I don’t know if you know all of these brands, being in Oz, but several of the poor-performing ones have those darned clear glass bottles, so photooxidation could be a big player in PV and polyphenols, depending on time out on the shelf vs. in a cardboard box — or in an air conditioned area vs. one that is in the California heat …

Thanks again!

One thing that I did notice but didn’t mention in the post (as it seemed out of place), was the variablity in the chemistry of the big name brands across the different cities where the oils were sampled from. The differences in polyphenols alone tell me that within the same brand the batch variation in the oils is high. That surprises me as I would have thought that the big producers would have put a lot of effort into ensuring a consistent product in terms of style. Certainly for the few companies who I have blend for in Australia, that is their number one priority. They don’t like the idea of having a mild oil out their under their label one year and a ‘cough bomb’ out there the following year. In fact they are usually very specific about how much bitterness and pepperyness they would like to build into the blend.

RG

Thanks as usual for an informative post! I am guessing that some readers may have trouble downloading from the URL as it appears in this entry; folks who couldn’t get it to work should be able to download the UC Davis report testing extra-virgin olive oils at the link I just made.

Readers should really download a copy, because the report is even more useful than the blog post suggest, since it not only includes hard-to-find numbers on polyphenol content, but also Names Names for the specific tested brands. And, they bought oil at 2 or more sites for each brand, and included a range of additional, validated chemical indicators of oil quality beyond those required by IOC and USDA standards.