Presenting Sunny Isle Jamaican Black Castor Oil 4oz Regular. Sunny Isle Jamaican Black Castor Oil is processed the traditional way. Our Organic seeds are roasted and ground by a manual Grinder and then the crushed beans are boiled to extract the 100% pure, dark brown, organic oil. It's the best quality oil on the market. Why you may ask? Compared to other brands it is the darkest Jamaican Black Castor Oil because we roast our beans longer which produces more Ash Content in our oil than any other oil on the market. More ash content increases the effectiveness of the oil. Therefore the Sunny Isle brand will strengthen and increase the length of your hair faster than any other brands on the market today.