We were really lucky to have James and Richard from Mount Zero visit our Prahran cafe to host an olive oil tasting class for our staff. We learned so much on the day and have gained a new-found appreciation for olives and their oil! We took some notes from the session and Richard shared some photos from his family's olive oil farm. Enjoy the read & peek...
Oxidisation is a big plays a big part in lowering the quality of olive oil. It can happen at many stages, but it can happen initially during picking - bruising of the fruit skin as it is being harvested can cause oxidisation.
Oil is extracted from the olives by mashing them, or beating them and mixing them up, then the mashed olives, pip, and skin are put through a centrifuge which separates the pulp, water, oil and skin. Heating the oil during the mashing or pulping can increase the amount of oil that is extracted, although over extracting can produce negative flavours. Up to 30% of the olives weight can be extracted as oil, although only 10-22% is a common extraction.
Good quality olive oil can be used in almost any type of cooking. One of the myths about olive oil is that you can’t use it for frying. While it’s true that it has a lower smoke point than some other oils, this is at 220 degrees Celsius, which is at the higher end of cooking temperatures anyway. A famous chef is reputed to have used the Mount Zero Picual olive oil exclusively while cooking in Melbourne, for frying steak but also finishing the meat while it was served.
Olives in Victoria are harvested in April through June, the opposite of the northern hemisphere where olives are harvested October - December. While olive oil does not “go off” as such, it does oxidise quite easily. Factors like exposure to heat, oxygen and light expedite this oxidisation. Mount Zero have labelled an 18 month expiry date on all of their olive oils, although consuming within the 12 months is recommended to get the most out of them. As a broad rule, if an olive oil does not have a harvested date printed on the packaging, it is safe to assume it is not very fresh.
Mount Zero grows predominantly Manzanillo variety olives, about 6500 individual trees. Each tree will produce from 30-60kg of fruit, and from this will yield 5.2kg - 10.2kg of olive oil per tree. The average extraction of oil from the fruit of these trees varies from 15%-20% of weight of fruit. The amount of oil in the fruit depends on the ripeness or age of the fruit on the tree - the longer the fruit is on the tree, the more oil the fruit will contain. The downside is that the flavour of the oil diminishes past a certain point of ripeness, the best oil is produced when the fruitiness is in harmony with the bitterness and pungency. Pruning occurs to promote higher fruit yields. Olives grown on branches that are 2-3 years old produce the most fruit, so pruning is done for all trees.
We tasted six samples, and I have included our group notes as a guide. Pungency is the burning sensation of the oil in your mouth - similar the the peppery sensation of rocket or green peppercorn. It can be very fast acting, or slow and building pepperiness, or simply mild.
Sample 1. Arbequina variety
Aroma: intensity 2/10, herbaceous, apple, un-ripe banana, honey suckle
Fruitiness: intensity 2/10, not a lot of fruitiness, a little apple-y, honey
Bitterness: intensity 2/10 low-none, very mild
Pungency: 1/10 soft-slow, mild aftertaste.
Comment: Flat, mild
Sample 2. Manzanillo, Frantoia
Aroma: 4, more grassy, lemongrass, melon
Fruitiness: 3, medium, low, mild
Bitterness: 3, low-medium
Pungency: 5, slow, spicy, surprise! green peppercorn
Comment: quite heavy in texture, still flat of flavour, more ripe.
Sample 3. Picual
Aroma: 5, herbaceous, rocket, olive leaf, leafy, chlorophyll like, greenish
Fruitiness: 4 a little fruit
Bitterness: 6, quite a bit more, rocket-like, mild, pleasant
Pungency: 6, quicker, faster peppery.
Sample 4. Koroneiki
Aroma: 5, ripe banana, a little vinegar, peppery-rocket
Fruitiness: 6, melon, fruity, banana like
Bitterness: 5, bitter, radicchio
Pungency: 4 soft, slow and soft spiciness,
Sample 5. Picholine
Aroma: 5, herbaceous, rocket, peppery, clean
Fruitiness: 3 low, no distinctive fruitiness
Bitterness: 8, high, quite intense, hoppy but not drying sensation
Pungency: 5, med pungency.