This is my first time homebrewing.
My first batch of witbier Has been in the secondary fermenter for 3weeks now. How do I know A) when it's done? B) if it's ok to drink
I see a whitish greenish line around the top layer on the edges. Is that ok?
Thanks in advance.
The greenish white line is likely to be "trub"...also known as "gunk" from fermentation and hops. Although it's hard to say for certain without a pic, my guess is that you're fine. You'll know it's done when you take hydrometer readings on several days and get the same reading each day. The only way to know if it's OK to drink is to taste it.
You should be able to tell if there is any fermentation still happening by observing the fermentation lock. I assume that after 3 weeks your brew is done, but if your lock is still bubbling (say even every 2-3 minutes) then some fermentation is continuing. You don't say what the ambient temperature is, but assuming a proper range, 65-75F, then you are probably ready to rack before bottling. Because it's wheat beer, it will never be clear, so you can't tell if fermentation has stopped from the beer starting to clear.
The green line is likely trub, as already mentioned. But that might mean you need to rack this liquor off of the yeast, if you haven't done so yet, if you don't want a lot of that stuff in your bottled beer.
