Disclaimer - I have no idea about this but was just thinking about unbleached/raw cotton and my craft box came to mind lol
What about the cotton used for candle wicking it is the same unbleached colour as as the calico it is embroidered onto? (just to be really clear its a ball of yarn from craft shops for sewing not for candle making hehe)
I have read people here using candle wick cotton (yes, the kind used for candle making) but not the type of which you speak. However, if it seems like people are using all kinds of cotton, trying to lean towards those with the least amount of processing/manufacturing additives. <?> If that's how you'd say it.
I ended up with Lion's brand organic cotton yarn as the dyes are natural, so got the lightest color, Almond. Then I got Sugar & Cream undyed 100% cotton yarn (not organic), both from Joanne's.
The Lion's organic yarn is worsted, which I didn't want but didn't have a choice. This means it is twisted in a puffy way that makes the string of yarn uneven in thickness. It also has a smell to it, but it's the only organic cotton yarn I could find locally.
The Sugar & Cream is the equivalent of WalMart's Peaches & Cream, undyed cotton, but not organic. A nice, even yarn. (A sewing forum said the P&C is softer and fuller than S&C, but could not get P&C, so...)
I got so excited to try it, I cut a length of each and boiled in the microwave using distilled water in a pyrex bowl (some people reported a metallic taste after boiling in a pot). Boiled a couple minutes, discarded the water, refilled and boiled again a few minutes (impatient).
Hated the result, so will try boiling for 20 minutes later and try it again. The taste was exactly like the cotton balls I tried.... tastes like I'm vaping the steam off an iron while steam-pressing an old musty cotton shirt that's been hanging in the closet forever. BLEH! Couldn't even taste the RY4 at all. Tried to keep going thinking it just needed a few minutes, but NOPE! Threw that sucker out.
Meanwhile the good news is I made the coils perfectly.
I sure hope boiling 20 min makes a difference or I will be looking at high-resistance silica... which I'm not crazy about only b/c nobody really knows how safe it is. But it seems like silica has less taste to it than cotton. At least until I do the cotton right.
