This standard applies to the testing of honey and specifies a method for the determination of the hydroxymethylfurfural (HMF) content. The Winkler photometric method is used for this determination. The standard deals especially with the quality aspects of honey. Honey is warmed up so it is easier to bottle and liquefy it after crystallization. In order not to damage them during this procedure, heat-sensitive constituents, for instance enzymes, should only be heated for a short time and the temperature should not exceed 40 °C. The substance hydroxymethylfurfural (HMF) is formed from fructose when honey is exposed to higher temperatures. Freshly extracted honey does not contain any HMF. If it is stored in a cool place, which is below 14 °C, the HMF value increases only slightly. However, if the storage temperature is higher than 21 °C, the HMF content can increase to 20 mg within a year and at 70 °C to values of 80 mg within 20 hours. The Deutsche Honigverordnung ("German Honey Regulation") does not specify a maximum temperature for the processing and bottling. The only quality criterion for tablehoney which has been specified by law is a maximum HMF value of 40 mg per kilograms. If the value is higher, it may be sold only as baker's honey or industrial honey. If tablehoney is additionally advertised with designations like "cold-pressed", "with natural content of ferments", "raw" or "natural", it may have an HMF value of not more than 20 mg per kg according to the German guidelines. This standard has been prepared by Working Committee NA 057-05-08 AA "Honiguntersuchung" ("Analysis of honey") of NAL and constitutes a revision of the currently valid standard of the 1992 edition of DIN 10751-1. The Committee responsible for this standard is NA 057-05-08 AA "Honiguntersuchung" ("Analysis of honey").