For what it's worth:
"None of the ingredients in the nutrient contain gluten, but, we do process it in a facility that utilizes gluten containing ingredients (dry malt extract). Though the potential for cross contamination is very minimal, at this time, we do not take measures to prevent this and therefore do not claim the nutrient is a GF product.
Please let me know if you have questions.
Wyeast Laboratories, Inc."
Very timely response from them (<2 mins). Good info to have.