After filtering the wine, winemakers may request a filterability to ensure the wine will not clog up the filter during bottling. The analysis for this is a simple procedure and it can really benefit the bottling stage go swiftly.
Method 1
During class we learnt a method of testing filterability by tracking the mLs that pass through the .45 pore size filter and timing this. First you run through your sample for 30 seconds. After 30 seconds you need to record how many mLs will pass through in the next 60 seconds. Let another 30 seconds pass from the first reading, and the final mLs are recorded from the next 60 seconds. By dividing the first volume to the second volume you receive the filterability ratio. If the amount is between 1.0-1.5, the wine is good and will not clog up the filter, if its 1.5-2.0 then it is a moderate reading and may need to go through the filters at a slower rate. If the amount is greater then 2.0 then its poor and will need to be filtered again.
Method 2
Another method for testing filterability is by obtaining 500mls of your sample and putting it in to 2 X 200ml volumetric flasks. Using the same vacuum filtration pump with a 0.45um membrane filter pad and a timer, start by putting in 50mls of wine in to the receival cup. Once this wine has filtered through you then simultaneously start the timer and dump the first 200ml into the receival cup. After the wine has evacuated the filter pad you then note the time (T1) and at the same moment pour the next 200ml sample in. Once this has filtered all the way through you stop the timer and note the time (T2).
Results
First you convert the time into minutes, then the formula is FI = T2 – 2 x T1.
For example, if my T1 was 1:43 and T2 was 3:28
T1= 103
T2= 208
FI= 208 – 206
F1 = 2
Anything less then <20 is considered a pass!
By Emma Gordon