Walnut oil is a speciality oil that is best used on salads, desserts and pasta. It is known for its rich flavour and for being sensitive to heat. When walnut oil is heated it can take on a bitter taste. The health benefits of walnut oil are significant in that a small amount of oil contains calcium, zinc, iron, selenium, magnesium, vitamin E and niacin. Walnut oil also contains vitamins B-1, B-2 and B-3. It takes a large amount of walnuts to make a small amount of walnut oil; therefore walnut oil tends to be sold at a higher price than other natural oils.
Collect or buy 3.63kg. of dry walnuts in the shell. Use a nut cracker to crack open the walnuts. Take the meat out of the shells and place them in a clean bucket or large bowl.
Place a bucket or large bowl under a meat grinder to collect the ground walnuts. Pour a small amount of walnuts into the meat grinder and grind until fine. Continue this process until all of the walnuts are ground up.
Pour the ground walnut meat into a cooking pot. Add enough water to barely cover the top of the walnuts. Heat the walnut meat for 45 minutes. Stir the mixture constantly.
Begin placing the cooked walnut meat in the oil press and press the walnuts to squeeze out the oil. Be sure to keep a bucket or bowl under the oil press to collect the oil. Continue this process until all of the meat has been pressed. Eight lbs. of walnuts should produce about 2 qts. of oil, though results will vary by the quality of the walnuts.
Use a cheesecloth to filter the walnut oil. Place the cheesecloth over the oil that is collected and pour the oil into stainless steel storage containers or bottles.
Store walnut oil in a refrigerator for two to four months.
Throw away any unheated walnut oil that has a bitter taste. Bitterness is a sign that the oil has turned rancid.