The C4 sugar test is a general qualification procedure for marketed honey. Current standards limit the amount of C4 sugars in honey to 7%. Most floral types of honey produce stable C4 sugar test results over the period of their shelf life. High-quality mānuka honeys were shown to inflate their C4 sugar content when stored, whereby significantly devaluing the product. This effect is exacerbated by the practice of ‘ripening’ fresh honeys, especially by heating. We at Analytica did a thorough investigation on that phenomenon and came up with a kinetic model, which reliably forecasts the change in apparent C4 sugar in mānuka honeys.