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Lactic fermentation

Fermentation steered towards lactic acid bacteria rather than yeast. Produces a creamy, yoghurt-like sweetness quite unlike anything else.

Lactic processing manages fermentation so that lactic acid bacteria dominate rather than yeasts — the same organisms responsible for yoghurt, sauerkraut and sourdough.

How it is done

By restricting oxygen and controlling temperature, producers create conditions where lactic bacteria outcompete other microbes. Sometimes cultures are added directly.

The fermentation typically runs long and cool.

The result

A distinctive creamy, dairy-like sweetness — yoghurt, condensed milk, sometimes a savoury edge — alongside intense tropical fruit.

It is genuinely different from anaerobic or carbonic processing, and recognisable once you have tasted a few.

Why it works

Lactic acid is softer and rounder on the palate than the acetic acid that dominates uncontrolled fermentation. Shifting the microbial balance shifts the acid profile, and with it the whole character of the cup.

The risk

Poorly controlled, lactic fermentation goes sour and vinegary like any other. The precision required is why these lots are expensive.

Where it comes from

Colombia and Costa Rica principally, with the technique spreading quickly.

Brewing it

Filter, very light roast. The creaminess also shows well in an immersion brewer.

What you need to make it

The equipment this actually requires — not a shopping list, the shortest route to doing it properly.

  • The reference pour-over Manual brewers

    Hario V60 02 Ceramic

    60° cone · spiral ribs · 1–4 cups

    The most transparent cup you can brew for twenty euros, and the least forgiving. Ceramic holds heat where plastic does not — and the open bottom means your pour, not the dripper, decides the coffee.

    Best for: Someone who wants to taste what a single-origin coffee is actually doing.

    8.2/10

    ≈ $25 / £20 / 22 €

  • Best filter grinder Grinders

    Fellow Ode Brew Grinder Gen 2

    64 mm flat burr · filter only · single dose

    64 mm flat burrs, near-zero retention and a footprint the size of a mug, built for filter and honest about not doing espresso. For pour-over it is the clearest grind you can buy at this price.

    Best for: V60, Chemex, AeroPress and batch brewing, where clarity is the whole point.

    8.7/10

    ≈ $345 / £275 / 300 €

  • Best pour control Kettles

    Fellow Stagg EKG Pro

    0.9 L · ±1 °C hold · counterbalanced gooseneck

    The best-pouring kettle sold, and the hold function matters more than the thermometer. Expensive for boiling water — but if you brew pour-over daily, it is the accessory that most improves the cup.

    Best for: Daily pour-over, where flow rate is the variable you are trying to control.

    8.6/10

    ≈ $195 / £165 / 180 €