Honey moisture content calculator
A drop on the prism, a reading on the water scale: enter it here to see whether your honey will keep, whether it makes USDA Grade A, and what blending two batches would give.
How it is calculated
The US reference points
| Moisture | What it means |
|---|---|
| 18% or less | Keeps well: the wild yeasts naturally present in honey stay inactive. A good target for honey stored warm or creamed. |
| Up to 18.6% | USDA Grade A and Grade B line: at least 81.4% soluble solids. The figure most US buyers and fairs use. |
| Up to 20.0% | USDA Grade C. Also the Codex limit for most honeys, which Wisconsin makes the legal definition of honey (rule ATCP 87.015). Fermentation risk rises above 19%. |
| Up to 23% | Florida's standard of identity for honey (rule 5K-4.027). Codex also allows 23% for heather honey (Calluna). |
There is no federal moisture limit: FDA's 2018 honey labeling guidance deals with names and added sweeteners, not composition, and USDA grading is voluntary. If you put "Grade A" on a label, though, the honey must meet the standard, 18.6% included. Programs such as NY Grown & Certified ask producers to confirm 18.6% or less in capped frames before extraction and to log the moisture of each batch. Your own state may have its own honey standard: ask your state department of agriculture.
Blending two batches
blend moisture = (weight A × moisture A + weight B × moisture B) ÷ (weight A + weight B)A weighted average, valid for two honeys you plan to combine in a bottling tank. It is not a way to rescue wet honey: the calculator flags any batch above the limit you chose. The full method, with refractometer calibration and drying wet supers, is in our guide to harvesting honey. Record each reading in your honey extraction log.
Frequently asked questions
What is the ideal moisture content of honey?
18.6% or less, which is the maximum for USDA Grade A and Grade B extracted honey (at least 81.4% soluble solids). Many beekeepers aim for 18% or lower if the honey will be stored warm or creamed. Extract capped frames: uncapped honey holds more water and more yeast.
Is there a legal moisture limit for honey in the US?
Not federally. FDA's honey labeling guidance sets no moisture figure, and the USDA grades are voluntary. Some states set one: Florida's honey standard caps moisture at 23%, and Wisconsin requires honey to meet the Codex standard, which allows 20% (23% for heather honey). If you print a USDA grade, the honey must meet it.
What happens if honey moisture is too high?
It can ferment. Honey always carries wild yeasts: below about 17% water they stay inactive, above about 19% there is a real risk, and from 20% they multiply freely. Fermenting honey foams, smells sour or of alcohol and tastes sharp. Granulation makes it worse, because the liquid between crystals is wetter.
How do you use a honey refractometer?
Calibrate it each season, for example with extra virgin olive oil set to 71.5 Brix (27% water). Let the instrument and the honey reach room temperature, put a drop on the prism, close the cover and read the water scale. Sample several frames, including the least capped, and clean the prism between readings.
How do I lower the moisture of honey?
Dry it before extraction. The University of Florida suggests stacking supers crisscross in a small, warm room with a dehumidifier and a fan for a day or two. In small hive beetle country keep it short and sealed. Blending a wet batch into a dry one only spreads the problem and hides it.
Does honey moisture affect USDA grade?
Yes. Grades A and B need at least 81.4% soluble solids, a maximum of 18.6% moisture; Grade C needs 80.0%, or 20.0% moisture. Below that the honey is substandard. Flavor, absence of defects and clarity are also scored, while color is classified separately on the Pfund scale and does not affect the grade.
Sources
- United States Standards for Grades of Extracted Honey (effective May 23, 1985), USDA Agricultural Marketing Service
- Guidance for Industry: Proper Labeling of Honey and Honey Products (February 2018), US Food and Drug Administration
- Florida Administrative Code rule 5K-4.027: Standard of Identity, Honey, Florida Department of Agriculture and Consumer Services, via Cornell Law School LII
- Wis. Admin. Code ch. ATCP 87 (ATCP 87.015 honey standard), Wisconsin State Legislature
- Revised Codex Standard for Honey (Codex Stan 12-1981, Rev. 2001), FAO/WHO Codex Alimentarius, via the International Honey Commission
- Honey food safety (NY Grown & Certified honey producer manual), New York State Department of Agriculture and Markets
- Refractometer: all you need to know (Hanna Bäckmo), Bee Culture
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