I made my fina a few weeks ago, with heat, and then I put it up in my closet. I took it out yesterday and looked at it and it looks like there is a a stain on the inside of the bottle. Almost like if you leave dirty water in a container there is that ring around the container, it looked like that but it was the dark brownish-red color. Is there something rong with it or does this happen sometimes and there should be nothing to worry about?