All suet is fat, but not all fat is suet. Nor is it always beef fat.
The best suet comes from the fat that grows around the kidneys in cows and sheep.
Butter and shortening melt earlier in the cooking process, blending right into batters. Suet, because of its higher melting point, melts much later: after the batter has begun to set. When it melts, it leaves spaces in the setting batter, making the batter lighter than butter or shortening can.
Many British recipes call for suet because it is a very standard ingredient that is easy to buy off the shelf in the UK.
In Canada, you can buy bags of frozen suet by companies such as “Maple Leaf” in supermarket chains , particularly around Christmas.
There are a few different brands of boxed, shelf-stable vegetable suet that get imported to North America.
You can get balls of suet destined for bird feeding but it’s very unlikely that they would be food-grade for humans, or that sellers would risk saying they were.
To render your own. Stick raw fat in a baking dish in a hot oven, and melt it. Throw out any solids remaining, and pour carefully into a large bowl to cool. As it starts to solidify, mix in ice water with a hand mixer or whisk until it gets very solid. Pour off the water, and put in fridge to cool and dry. Roll up into balls, wrap in plastic film, and freeze until needed. Grate frozen if required when you go to use it.
If you are going to shred suet, have it really cold to start with; the colder the better.
Lard, shortening, butter, vegetable suet, bacon fat.
1 oz / 30g suet, shredded = 1/4 cup shredded suet
Freezes well, so don’t hesitate to buy more than you need at present, especially if you’ve had a hard time finding it in North America. And the bonus is that when it’s frozen, it grates really easily (many recipes call for you to grate it.)
Literature & Lore
“Suet was highly recommended for frying purposes. In England nothing but suet is used for frying. It is without odor. It is well to use a small amount of cottonseed oil with it. Cocoanut butter is good but then it is unnecessary to buy any frying material. Mutton suet is preferable to all other suets, but all the fiber must be carefully removed or tallow will be found on the plate on which it is served. In rendering suet keep water away from it.” — Jorgenson, Judith. Around The Evening Lamp. Des Moines, Iowa: Des Moines Daily News. 2 June 1896. Page 2.
Comes from an old French word “su” which meant hard animal fat or tallow.