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This is NOT true! It has been stated numerous times on the net that
distilled alcohol and vinegar made from wheat THEORETICALLY should
not be harmful for the reasons you state. But I have seen numerous
msgs from this group where "very sensitive" people have reported reactions!
Certainly contamination could occur after distillation, since wheat
is present in the environment.
Of course it is not conclusive either way! But it certainly is NOT
harmful to alert those that care to these fact!