What goes wrong

It seized or went grainy

Updated October 2026

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What happened Where the water came from If it happened in one jar, it was the customer If it happened across a batch, it was you It connects to the safety pages You cannot rescue it, so prevent it References

A batch that has gone thick, dull and grainy has met water, and the amount needed is far less than people expect.

What happened

A small amount of water in a fat-continuous system pulls the solids together instead of leaving them dispersed. The result is stiff and granular and no amount of further mixing or warming brings it back. Once it has happened to a batch it has happened.

Where the water came from

Jars or utensils washed and not fully dried.
Condensation, from filling warm product into cool jars or storing warm jars in a cold room.
An ingredient that brought water with it, such as honey or a fruit addition.
A wet cleaning routine in the production area that nothing was dried after.

If it happened in one jar, it was the customer

A wet knife is the usual explanation for a single jar going grainy after opening. That is worth knowing and worth a line on the label, and it is not something you did.

If it happened across a batch, it was you

Which narrows it to the jars, the fill temperature or the cleaning, and the batch log should distinguish them. This is a case where the fill temperature column earns its place.

It connects to the safety pages

Water in a low-moisture production environment is not only a texture problem. The same damp that seized a batch is the condition that supports growth somewhere in the room, so a seizing incident is worth treating as a signal rather than an annoyance.

You cannot rescue it, so prevent it

There is no reheating, no extra oil and no longer mixing that undoes a seized batch. It can sometimes be used as an ingredient in something where the texture does not matter, and it is not the product you set out to make. Every minute spent making sure jars and utensils are bone dry is worth more than any recovery technique, because there is none.

The habit that prevents it is boring: wash jars well ahead, dry them fully, store them covered, and keep anything that has been near water away from the bench where the product is.

References

Michigan State University, Center for Low-Moisture Food Safety. Thermal death kinetics of Salmonella in peanut butter as influenced by water activity, and the related work showing that Salmonella becomes more heat resistant as water activity falls. canr.msu.edu

United States Food and Drug Administration. Guidance for Industry: Measures to Address the Risk for Contamination by Salmonella Species in Food Containing a Peanut-Derived Product as an Ingredient. fda.gov

Written from federal regulation, FDA compliance policy and published food-safety research, not from a laboratory. The kill-step pages describe a real hazard and are a starting point for a conversation with your state department of agriculture and a process authority, not a determination that any roast you run is adequate.