Not all the flavour standard powder has dissolved. Is this normal?
Are you sure that it hasn’t? If the beer is cold, allow 5 minutes and make sure that you have mixed the flavour standard and beer as recommended in the instructions. In calibrating the flavour standards, we have allowed for tiny amounts of material which might not fully dissolve before use. This should be no more than 0.1% of the material by weight. It will be almost invisible and will have no impact on the flavour of the material.
