Column IJsbrand Velzeboer: Fat - flavor hero or smelly villain?

Fat is high in calories. Eat a full pack of butter and you’ll have enough energy (1,890 kcal) to keep your internal furnace burning for a whole day (the greasy mouth and diarrhoea will pass on their own). But fat is more than just fuel.

One of fat’s key qualities is its ability to absorb and carry aromas. A ribeye or pork belly cooked with the fat cap intact delivers far more flavour. Lean meat simply can’t compete. A smoked sausage only hits the mark when the juices burst out as you bite in. The soft drink and jam industries know this too: many fruit aromas are fat-soluble. To prevent them from separating like an oil slick in the final product, they're dissolved first in a bit of propylene glycol. That way, they blend easily into watery drinks or jams.

Chemically, fat is a triglyceride – a glycerol molecule (think of the capital letter “E”) with three fatty acid chains attached. Imagine these chains as three shoeboxes stuck to the E. The more “holes” in the boxes, the more unsaturated the fat is. The longer and more saturated the chains, the higher the melting point – up to 72°C in some cases.

Here’s a strange historical fact: fat supported Napoleon’s wartime logistics, and helped Dutch windmills long before ball bearings were invented. The sliding bearings of wagon wheels and mill sails were greased with fat. Applying it was a filthy job.

Rancid fat, on the other hand, can stink terribly. That smell comes from volatile fatty acids breaking free from the glycerol molecule – a process we call hydrolysis. The smell of the shortest fatty acid, acetic acid, is still relatively tolerable. But butyric acid? That one makes life unpleasant. It’s the scent of sweaty socks and a key note in the aroma profile of Dutch cheese.

Then you have caprylic and caproic acids – their names come from caprae, Latin for goat. These volatile fatty acids are responsible for that unmistakable “billy goat” smell. And trust me: old billy goats can reek. So can uncastrated boars and old sows. Their meat tends to carry a strong, urine-like odour. This type of meat often ends up mixed into bargain BBQ sausages.

So be warned this summer: leave the goat (and the sweaty socks) at home.

IJsbrand Velzeboer
Curative food technologist