Moisture Meter
An instrument that reads the moisture content of green or roasted coffee.
Overview
Moisture content drives almost everything about how a batch behaves: how much heat it absorbs early, how much weight it loses, and whether it stores safely. A moisture meter gives you that number before you commit a batch to the drum.
Using it well
- Take three readings from different parts of a bag and average them. Moisture is rarely uniform.
- Around 10.5-11.5% is a comfortable green coffee range for most profiles.
- Drier beans roast faster and lose less weight. Expect your usual profile to run short.
Some meters use sharp sampling electrodes. Handle with care, keep away from children, and never probe anything other than coffee with a dedicated instrument.
Why this matters
The moisture meter sits in the charging stage of a roast. Getting it right removes one source of variation, which matters because roasting rewards consistency more than any single clever adjustment. Change one variable at a time, record what you did, and compare batches rather than judging any single roast in isolation.
If you are building a complete setup, start with the instruments that measure what is happening - a probe, a scale and a logger - before buying anything that promises a better result by itself. Measurement first, equipment second.
Educational content. Roast Lab does not sell this or any other product, and we do not accept payment for coverage. Specifications listed above describe typical ranges for the category rather than any specific model, and vary between manufacturers. Always follow the manufacturer instructions and safety documentation supplied with your equipment.
Related tools
Green Coffee Beans
Unroasted coffee in its raw, stable state - the input to every roast.
Storage Bin
An airtight container that holds a working supply of green coffee at stable humidity.
One-Way Valve Bag
A barrier bag with a one-way degassing valve, used for both green and roasted coffee.
Humidity Control Pack
A two-way humidity regulator that holds a container at a target relative humidity.