MLF.

Whilst I have been busy of late with activities that have frequently taken me away from Vinoland, Vinomaker has been hard at work down in Vinoland's cellar.  He has been filling his spare time with the fining and cold-stabilisation of the white wines he made last autumn and he has also been testing the red wines to see if they have completed malolactic fermentation (MLF).  MLF is over when all of the malic acid in the wine has been converted to lactic acid with the aid of malolactic bacteria.
The easiest way to assess whether or not MLF is complete is to perform a paper chromatography (PC) test.  PC is a relatively simple test which is done by placing tiny drops of wine, (and control samples of tartaric, malic and lactic acids), onto chromotography paper which is then placed in an eluting solution. The solute, which is rather smelly, wicks up through the paper separating out the acids from the wine samples by virtue of their differing molecular weights.  Each acid will move a characteristic distance up the chromatography paper thus making it fairly easy to identify the presence one of the aforementioned acids.
One could, of course, send samples of wine to a laboratory which specialises in these types of things for an enzymatic assay.  But where's the fun in that?  This is winemaking and having physical evidence of a small natural wonder, albeit in the form of a tie-dyed piece of blotting paper,  is one of the more entertaining aspects of turning grape juice into wine.