Heart
Also known as pork heart, beef heart, Herz, coeur, cuore, corazón, serce
Pure working muscle with almost no marbling, the densest and darkest lean on the animal. It behaves like meat rather than like offal, which makes it the least alarming of the organs and the most useful in a sausage.
Heart is an odd member of the offal family because it is not really an organ in the way liver and kidney are. It is a muscle, and specifically the hardest-working muscle in the body, contracting continuously from before birth. Everything about it follows from that: it is extremely dense, very dark, packed with myoglobin, rich in iron, and it carries almost no intramuscular fat because it burns its fuel rather than storing it.
For a sausage maker this is a genuinely useful material. Heart is very lean, it grinds cleanly, and it brings a deep colour and a mineral, beefy depth that lean muscle does not have, without the strong organ flavour of liver or kidney. It is used across the eastern European and German traditions in the cooked and coarse sausages, in Polish kiełbasa formulas alongside tongue and head meat, in blood sausages, in some Italian preparations and in the French andouille family. It has always also been the economical lean, and there is no shame in that.
What it will not do is carry a sausage on its own. With almost no fat and a dense, slightly chewy fibre, heart-heavy formulas turn dry and rubbery, and the texture is noticeably firmer than the surrounding meat in the finished slice. Most traditional formulas keep it well under a quarter of the mix and pair it with a fatty cut.
Preparation matters and is straightforward once known. The heart is a pump, so it is full of structures that should not go into a sausage: the valves and the tough fibrous tissue around them, the large vessels at the top, and any blood clots inside the chambers. Split it, rinse the chambers thoroughly under cold water, and cut away the valves, the vessels and the thick silverskin on the outside. The remaining wall is clean, uniform muscle. Some traditions soak it briefly in cold water to draw out remaining blood.
Beef heart is the same tissue, considerably larger, and is the traditional base of biltong in some households and of a range of dried and cured products. It behaves the same way and wants the same trimming.
Heart keeps better than liver or kidney, being muscle, but it is still offal from a hygiene point of view: it is handled early during dressing and it wants prompt chilling and use.
Temple element. Pillar, Meat Quality