Lactic Fermentation

A fermentation managed so that lactic acid bacteria (LAB) — the microbes behind yogurt and sourdough — become the dominant microbial players, producing lactic acid as their main metabolite.

Producers create conditions LAB prefer: low oxygen (often sealed tanks), moderate temperatures, and enough sugar to feed on. Some inoculate with LAB starters directly; others rely on the natural population and manage conditions. pH is tracked so the ferment stops at the intended acidity.

Lactic acid and related compounds give the cup a round, gentle acidity and a texture often described as creamy or silky. Fruit flavors tend to read as dairy-adjacent — think peach yogurt or cream soda.

It produces a distinctive mouthfeel-and-sweetness profile that stands out in cupping, using microbiology the producer can learn to steer.

Creamy, round, silky; dairy-adjacent descriptors like yogurt, milk chocolate, cream soda, and soft stone fruit are common.

LAB ferments pushed too far trend toward sour dairy or over-run acidity; contamination with unwanted bacteria can introduce off flavors fast.

Only when inoculated — some producers add a selected LAB starter culture. Otherwise nothing but managed conditions and the coffee's own microbes.

No dairy or flavoring of any kind is added. 'Creamy' describes lactic acid's effect on texture and perception — the coffee is still just coffee.

Experimental microlot producers in Colombia, Ecuador, Costa Rica and Peru; growing interest worldwide.

Mostly Latin American microlots at high altitude.

Colombian and Ecuadorian 'lactic' lots (often Pink Bourbon or Sidra) sold by experimental-minded roasters.