Processing has become the most experimental part of coffee production, and the labels have outrun any standard.
The ones you will see
Anaerobic — sealed, oxygen-free fermentation. The broad category.
Carbonic maceration — whole cherries under CO₂, fermenting inside the intact fruit. Borrowed from Beaujolais.
Yeast inoculated — a specific commercial yeast strain added to control the fermentation. Reproducible, and the strain often determines the profile.
Lactic — fermentation steered towards lactic acid bacteria. Produces creamy, yoghurt-like, dairy sweetness.
Thermal shock — hot and cold water baths between fermentation stages, to control microbial activity.
Double fermentation — two distinct stages, often anaerobic then aerobic.
Extended fermentation — simply longer, often 48 to 120 hours.
The problem
None of these terms is defined or regulated. Two bags labelled anaerobic can be radically different, and some producers use the words loosely.
How to buy them
Read the tasting notes rather than the process name. They will tell you far more about what is in the bag.
And expect intensity. These processes are chosen to produce loud coffee.
Brew them clean
Filter, black, no milk. They are built to be tasted, and milk wastes them entirely.
Last reviewed 8 August 2026