Wood Pressed oils are a craze now. It can be seen by the products sold on Amazon, number of such outlets opened in towns because of the massive consumer preference. I don’t say they are wrong. Because they compare it with what they are consuming today i.e. the refined oil. But when they compare wood pressed oil with corresponding expeller pressed crude, filtered oil they are wrong. Health consciousness should rise, but they should also know what is healthy. Not go with what is popularly happening but scientifically reason it. Normally what is priced higher is good but not always. This fad about wood pressed oil is one such exceptional case.
We don’t debate that wood pressed oil is inferior to refined oil. Wood pressed oil is far superior to refined oil, period. But is it the best way to make oil? Answer is NO! Let us analyse this
2 types of machines to extract crude oil from copra
- Expeller – It is a fully closed arrangement, moisture should be completely removed from copra.
- Rotary – It is an open conical grinding machine, some moisture must be present in copra for lubrication.
Debate – which is better?
- Moisture causes rancidity in oil. So a better extraction mechanism should mean remove moisture. So expeller oil will have longer shelf life.
- Expeller squeezes more oil from copra than rotary. So extraction efficiency is better and oil cost will be lower. Oil cake will have lower oil content wasted.
- Greater quantity of copra can be crushed in expeller by increasing its size and supplying more power. This allows automation of entire process for larger scale.
- Oil extracted through expeller from dried copra can be filtered online through a filter press. Oil extracted from rotary from moist copra can only be filtered by sedimentation process which will take 7-10 days. So expeller gives faster throughput and requires lesser inventory.
- Because copra is heated to some extent, the oil smells and tastes better.
For rotary – only argument
- Copra is not heated, so the properties of coconut is retained.
What are the properties of coconut that would have been lost by heating? Common answer is vitamins. Any coconut oil contains 99.9% fat and 0.1% moisture. That means there is no other nutrient in coconut oil. Forget Vitamins, coconut oil has no carbohydrates, proteins and minerals. It is only fat.
Heating may go upto 80 degrees in expeller and 60 degrees in rotary. At both theses temperatures the fats don’t undergo any change. If heating of food is bad, then why do we cook rice, roast chapathis, pasteurise milk? Shouldn’t we consume them raw?
From rotary, it goes further down to wooden rotary instead of steel rotary.
- Extent to which oil is squeezed from copra is even lower. So oil yield is lower, labour cost is higher and hence oil cost is much higher.
- Heat generated is even lower. So there is no value addition of heat
- Wood absorbs moisture and oil and retains it. This is very bad for food hygiene and safety.
- When wood press is not used bacteria and fungus develops on the surface
So, we have argued that rotary oil is inferior to expeller oil and further wood pressed oil takes it a step further and is more inferior and more expensive.
Now, in expeller, roasting of copra before oil extraction increases the quality to another level by enhancing flavour, taste, aroma and shelf life.