I wanted to get your take on a possible contamination issue with several of my meads. I generally rack around 3- 4 weeks, after which (on some meads, not all) I noticed a thin film on top. I notcied this a couple weeks in the secondary (so on average, the meads are at the 6-8 week point when it develops). The film is translucent but noticeable, a bit like oil spread out on top of water. Some of these little film patches have bits of white growing on them. I'm not sure if its mold, or just some type of protein, or nutrient, that the yeast has caused to bind and float to the top. The white is not fluffy, but almost like really really tiny bits of rind from an orange. The oldest mead with this issue is now about 4 months old.
I clean and and sanitize all my equipment(1 Step for cleaning, Starsan for sanitizing), and add sodium metabisulfite to must prior to pitching yeast, and also during racking. All ingredients that I add (spices, fruit, etc) I boil for 15 minutes. However, I do NOT heat honey at all (as recommended by Ken Schramm). As such, the only thing I can think of is that the white stuff is perhaps coming from something that was already in the honey. (I should note, the honey I use is preheated and filtered --i have used Gunters, Dutch Gold, and the honey supplied by my local brew store). I have experienced this with Lalvin 71b-1112 and Lalvin EC-1118 and White Labs sweet yeast (I therefore dont think its due to one particular strain of yeast)
Does anyone know if this is normal for a mead in which the honey in the must is not heated or boiled? Anything I should be doing differently in terms of sanitizing/cleaning/sulfiting? I am working on uploading some pictures, hopefully will have them up soon. Thanks!