Why melted chocolate is too thick
Usually the product rather than the technique. Cocoa butter content decides viscosity, and no amount of heat compensates for not having enough.
If you read nothing else
Thick melted chocolate is usually the wrong product rather than the wrong technique. Cocoa butter thins it correctly; oil and cream thin it and destroy the temper.
The materials answer, which is usually the right one
Viscosity in melted chocolate is governed by cocoa butter content. Couverture carries a minimum of 31% and flows thinly; an eating bar at 26% does not; chocolate chips are formulated with less still, specifically so they hold their shape.
This is the whole explanation in most cases, and it is not a technique problem. A reader trying to dip strawberries in melted chips is fighting the product's design, and heating it further only risks scorching.
The temperature answer
Tempered chocolate thickens continuously as it crystallises and cools. A batch that coated thinly at the start of a session will coat heavily twenty minutes later, and the fix is a few seconds of warmth and a stir — not more, because two degrees too far destroys the temper.
If a batch was never in its working range at all, that is the cause: below about 29°C dark chocolate is thick and getting thicker.
The two things that make it worse
Water is one. Even a trace increases viscosity sharply before it seizes properly, so chocolate that has become mysteriously sluggish may have taken on a little moisture.
Over-crystallisation is the other: too much seed chocolate, or too long tabling, leaves more crystal than the batch needs and the chocolate thickens even at the right temperature. Warming to the top of the working range dissolves the excess.
Thinning it deliberately
Adding cocoa butter is the correct way to thin chocolate, at around 1–2% by weight, and it does not affect temper if the cocoa butter is added to the melt before tempering.
Adding oil, butter or cream does thin it and destroys the temper permanently, because those fats do not crystallise with cocoa butter. That is fine for a sauce and wrong for anything that has to set.
Covered in this guide
- Melted chocolate is too thickThe step-by-step remedy.
- CouvertureThe grade defined by the cocoa butter minimum that makes thin coating possible.
- Cocoa butterThe correct thinning agent, and why the alternatives break temper.
Sources
- ChocolateHQ editorial synthesis — ChocolateHQ(citation identity confirmed; passage not re-read)
- The Science of Chocolate — Royal Society of Chemistry(citation identity confirmed; passage not re-read)