The batch log
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The line
A batch log is one line per batch and it is the most valuable thing in a jam kitchen for the time it takes. Everything on the line is known at the moment you write it and unknowable a week later, which is the only reason it has to be written at all.
| Field | Why it is there |
|---|---|
| Date and lot code | The lot code on the jar has to point at this row |
| Fruit, source, condition | Poor fruit is a published cause of flavor loss |
| Fruit weight as used | The standard is a ratio by weight |
| Sugar weight as used | The other half of the ratio |
| Added pectin and acid | Both change the set and the process |
| Stop reading, and which test | The single most useful number for diagnosis |
| Jars filled, and size | Yield, and what you can declare |
| Process time and altitude used | So a seal failure can be traced |
| Anything unusual | Where the answer usually turns out to be |
Why the stop reading matters most
One field does more work than the rest put together, because it is the number that lets you compare two batches at all. Without it you have an anecdote about a batch rather than a record of one.
A soft set with a recorded stop temperature is a narrow investigation: it is the acid, or the proportions, or the batch was moved. The same soft set with nothing written down is a guess.
Why where it went matters too
Two of the published failures are storage failures. If every jar in a batch weeps it is the recipe; if some do, it is where they have been. That split only exists if you recorded which jars went where.
What it costs
Two minutes a batch, and the resistance to it is never about the two minutes. It is about writing while the pan needs attention, which is why the log lives next to the stove rather than in an office. A notebook with a pencil tied to it outperforms any system that requires washing your hands first.
Two minutes at the end of a run. The reason to do it is that the jar goes out with a lot code on it, and a lot code pointing at nothing is decoration.