Q: Is it true that cotton molds even when washed and dried properly?
A: We have sold thousands of organic cotton nut milk bags over that last 3 years and we just recently received our very first complaint [with a one star rating on Amazon] that our cotton bag hard to dry and smells. Please see our comment under amazon review for more details.
My first guess is that review was from someone selling synthetic (nylon or polyester) nut milk bags, or someone who lives in a very humid environment. We tested our organic nut milk cotton bags at 60 F with 40% humidity, and it dries within 1 hour. The fabric has small holes (open weave) so it dries faster without any reduction in strength than similar types of natural fabric .
FACT CHECK: Millions of people wear cotton clothing, numerous other cotton products and even use thick towels repeatedly after showering and simply hang them to dry in bathrooms that are often humid. If this claim was really true, then how do we account for all the cotton items properly left to dry (without a dryer) that are not moldy? Certainly, if you were to not properly wash and dry even synthetic materials can form: mold, fungus, bacteria...
If your bag is intended to be wet most of time (as it is for sprouting) or if you live in very moist (high humidity) environment then we recommend our Hemp nut milk bags which are sewn with linen threads. Hemp and linen both naturally have antibacterial & antimicrobial properties.