The cold squeezing out

What does "cold pressing" mean? It means that the temperature during the production of the olive oil mustn't go over 81° F. Over this limit oil quality decreases. 81°F limit is set by a European rule of 2002. Why just 81°F? Scientific literature deals with oil extraction even at 86°F and, in some cases, also 95°F. Heat helps the extraction but compromises some basic features such as acidity, peroxides and poliphenols. This affects the organoleptic part of the oil. Heat enhances sweet parts while fruity taste and vegetables sensations fade away. The community legislator, setting the 81°F limit made a compromise between the 86°F proposed by the oil producers and the 77°F chosen by the organic producers.

Is there also a "second pressing"?
Usually on the label, besides "cold extraction", we read the description "first pressing oil". Does it mean it's a better oil? And does this mean that there's also a "second pressing"? Actually it's an anachronism, a meaningless expression. The second pressing was made before the use of hydraulic presses yet. The most modern one reaches 600 atm. When the job was done by relying on animal strength or man power 2 or 3 pressing were necessary in order to extract all the oil. In that case distinction made sense and the "first pressing" oil was the best quality one. Today it's a meaningless expression. The extraction with the "periodic" system doesn't grant anymore, efficiency, according to standards required by the market and it has been widely taken over by the continous cycle machinery. The caption "first cold pressing" has remained in the UE rule, but has no distinctive value.