[pneuma8828]

Individuals with thyroid cancer have to observe low iodine diets during their treatments, and one of the sources of iodine that patients are told to avoid is dairy products. As a craft beer fan, lactose monohydrate is a common brewing ingredient, and my understanding is that production of food grade lactose monohydrate involves using ethanol to force crystallization out of milk. For this reason, beers with lactose are on the "no" list for low iodine diets. Can any scientists weigh in on whether this is necessary? Is there a simple test we can conduct on brewing lactose for the presence of iodine?

[Corribus]

Plenty of ways to detect iodine/iodide (which one are we looking for?) but few of them are accessable to the home chemist. Iodometric titration is possible but depending on the concentration range of interest it may not be sensitive enough for your needs. You could always send a few samples to a contract lab for iodine analysis.