Why Chocolate Turns White — Fat Bloom & Sugar Bloom Explained

Close-up of a dark chocolate bar with fat bloom — a pale grey, chalky film across its surface
Dmytro Minkov

Sometimes you unwrap a bar and it's wrong. A pale, dusty, greyish film has crept across the surface, the gloss is gone, and it looks faintly stale. It's called bloom — a lovely word for something so disappointing — and it's one of the most common questions we're asked. Here's what it is, whether you can eat it, and how to make sure it never happens to a good bar.

What bloom actually is

Cocoa butter is a strange fat. It can set into six different crystal forms, and only one of them — the fifth, if you're counting — is any good. That fifth form is what a chocolate maker is chasing when they temper: hours of heating and cooling and agitating, coaxing the fat into a tight, stable crystal lattice. It's why a good bar snaps instead of bending. Why it gleams. Why it holds its shape in your hand and then dissolves the instant it meets the roof of your mouth, which is a trick it performs because it melts at almost exactly body temperature.

That last part is the vulnerability.

Fat bloom: what heat does

A bar that melts at body temperature also melts in a warm room, a hot car, or a delivery van in July. It goes soft, then slack. And when it cools, nobody is tempering it this time — there's no maker standing over it. It sets however it likes, into whatever crystal form it can manage, which is generally the wrong one. The fat separates and migrates to the surface, where it dries into that pale, chalky film.

The bar is still edible. It's simply no longer the bar. The snap is gone, the gloss is gone, and it melts differently on the tongue — which means it releases its flavour differently, so the fruit and the smoke and the long finish somebody spent a decade coaxing out of a bean now arrive muffled, in the wrong order, or not at all.

It is, technically, still chocolate. In the same way that a piano dropped from a fourth-floor window is, technically, still a piano.

Sugar bloom: what damp does

There's a second kind, and it comes from the opposite problem. Store a bar somewhere cold and humid — the fridge is the usual culprit — and moisture condenses on the surface. It dissolves a little of the sugar, then evaporates, leaving behind a fine gritty crust. That's sugar bloom.

The quick way to tell them apart: fat bloom is soft and streaky and smears if you rub it; sugar bloom is dry and gritty and doesn't. Fat bloom is a heat story. Sugar bloom is a moisture story.

Is bloomed chocolate safe to eat?

Yes. Neither kind is harmful — bloom is a physical change, not spoilage. You can eat it, cook with it, or melt it down for hot chocolate, where texture doesn't matter. What you lose is the experience the maker built: the snap, the gloss, the way the flavour unfolds. For a supermarket bar, no great loss. For a bar someone fermented, roasted, and conched for seventy-two hours, it's a quiet tragedy.

How to store chocolate so it never blooms

Stop putting it in the fridge. It's cold and damp — the exact conditions for sugar bloom — and every time you take a bar out, condensation forms on the surface.

Chocolate wants a cupboard: cool, dark, dry, and steady, ideally 15–18°C, away from anything with a smell. Cocoa butter absorbs odours enthusiastically and indiscriminately; it will happily take on your garlic.

If it's genuinely sweltering and you have no cool room, the fridge is the lesser evil — but seal the bar in an airtight bag first, and let it return to room temperature inside the bag before you open it. The condensation then forms on the bag rather than on the chocolate.

How we handle it

Bloom is also why we ship the way we do. We send by express, we route around genuine heat, and we pack to the conditions on your delivery route — so the bars we send arrive as their makers intended. You can read the full detail on our shipping page.


A quick note, summer 2026: our new arrivals begin landing from September onwards. Bars marked Ships from September are open to reserve now — claim yours, and it ships as soon as it arrives. Everything in stock ships today, as normal.

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