Category Archives: Oils & Fats

Chilled Avocado Soup

The avocado is a favorite PHD ingredient: it is a fatty subtropical fruit with a fatty acid profile similar to that of olive oil (only about 14% omega-6). Native to the Americas, its wild ancestor, a small, black-skinned berry, is still found in southern Mexico and Central America. The avocado has been cultivated since at least 10,000 BC, making it one of the first domesticated plants in the Americas. After the European colonization of America, it spread slowly: Wikipedia says it was introduced to Indonesia in 1750, Brazil in 1809, South Africa and Australia in the late 1800s, and the Levant only in 1908.

Like all agricultural crops, the avocado has undergone extensive breeding. Over 80% of supermarket avocados are Hass avocados, which descend from a single “mother tree” on the La Habra Heights, California farm of mail carrier Rudolph Hass. Hass patented his tree in 1935.

In addition to their excellent (grade B in our book) fatty acid profile, avocados are nutritious. They have 35% more potassium per unit weight than bananas, a diverse range of vitamins and minerals, and are fiber-rich: 78% of the carbohydrate in avocados is fiber, totaling 7 g of fiber per 100 g serving.

This chilled avocado soup is a great summer food. Because it is so fatty, it is best paired with low-fat foods, such as a white fish like halibut or cod, shellfish, and potatoes.

Here is the recipe. Happy holiday weekend, everyone!

Beef Tallow

By reader request, we’re working on Perfect Health Diet versions of classic American foods. Next week we’ll start with French fries, then maybe chocolate chip cookies.

I think I mentioned once that we’ve been cooking with beef fat a lot. This is a little healthier than plant oils, since it has more phospholipids, cholesterol, and usable nutrients, lacks plant toxins, and is low in polyunsaturated fat.

Since we’re using beef fat to good effect in a lot of recipes, it’s about time to show how we render it.

Rendering Beef Fat

We buy blocks of beef fat from our local Asian supermarket. Here’s one:

This 1.28 lb (0.6 kg) package costs less than $2 and will make about 2 cups (0.5 liter) of oil.

We normally keep the package in the freezer until a day before rendering, when we move it to the refrigerator to let the fat soften a little. The first step is to cut the fat block up into pieces with a knife, and transfer it to a suitably sized pot:

Many people add some water to the fat at this stage. The good side of this is that the water prevents the fat temperature from rising above 100ºC / 212ºF. The bad side is that it makes a mess. We prefer to do it without water.

Start heating the fat at a very low setting and use a potato masher to break up the fat into finer pieces and squeeze out oil:

Soon it will look like this:

As soon as there is a significant amount of liquid oil, pour the fat and oil through a strainer to separate the liquid and solid fats:

The brown ceramic bowl is where we’re collecting the liquid oil. The solid fat caught in the strainer gets returned to the pot for more heating.

The reason for pulling out the oil is that beef fat contains a variety of components which have different melting points. In general, triglycerides containing short-chain and polyunsaturated fats have lower melting points, triglycerides containing long saturated fats high melting temperatures. Fats with lower melting points tend to be more chemically fragile. You don’t want to overheat the fragile oils, damaging them; but you need to be able to apply more heat to render the high melting temperature fats. The solution is to separate the oil from the fat several times, and gradually turn up the cooking temperature each time.

After the solid fat has been returned to the pot, you can turn the heat up a little bit, but not too much. We’ll do maybe 4 straining cycles before we’re done.

Here’s the oil collecting in our bowl:

At the end, this is what remains:

We don’t consider these cracklings to be healthy, and discard them, but Wikipedia says that cracklings “are part of all traditional European cuisines.”

The oil can be returned to the refrigerator and used as needed as a cooking oil. It solidifies upon refrigeration, but can be cut into pieces with a knife.

The whole process takes about 30 minutes.


At $4/liter (quart), rendered beef fat is cheaper than olive oil or coconut oil. Since few people buy beef fat, and many butchers trim fat from meat and discard it, you may even be able to get some free from a friendly butcher.

Rendered beef fat stands up to high cooking temperatures, is more nutritious than plant oils, and tastes great. Especially, as we’ll see next week, on French fries.