Page 21 - Grapevine July-Aug 2020

In The Winery

liters or 0.048 grams in 400 milliliters. This is any filter pad flavor. This same filtered wine
the same as the above calculation using 0.96 can then be moved forward to the protein test-
milliliters of a 5% solution in 400 milliliters. ing below. Use a new filter pad for each sample
to eliminate sloughing of the proteins from one
5. When adding the bentonite slurry to the wine – sample to the next.
make sure to be mixing the sample well yet do
not use shearing force mixers such as a blender. Simple Protein Test
Use the amount of agitation one can expect to
have in the wine tank while adding the fining Using the clean, dry 20x150 mm screw cap test
agents while mixing in the cellar. Always try tubes above fill each one about half full with the
and mimic the actual cellar experience as close- varying filtered fining trial levels created above.
ly as possible in the lab. If your lab has a mag- Label each test tube respective to its “pounds per
netic stir bar assembly these work very well. thousands” contents. For each wine have a control
sample that will go through the heat treatment
6. Continue to mix the samples thoroughly after described and one that will remain with no heating.
the addition of the agent or agents. Perhaps a
minute or so on a magnetic stir bar mixer. Collect each sample after filtering in the lab in its
respective test tube labeled 0,1,2…5.
7. Discontinue mixing and transfer the wine into a
labeled 375-ml wine bottle and place the screw Heat the test tubes in a crock pot with water to
cap on top. The label should reflect the addi- roughly 70 degrees C ( near 160 degrees F) for 8
tion rate of that sample such a 0, 1,2,3,4,5. hours. (See photo bellow) This is a great place to

8. Place, in a dark area, in the cellar or lab at or
near the exact wine tank temperature if possi-
ble.

9. Allow to settle overnight or several days.

10. Decant into a labeled beaker at least 250 mils of
the 400-ml samples from each fining trial. One
portion, approximately 50 milliliters per person,
may be transferred into pre-determined labeled
clean wine glass for visual, sensory and palate
evaluation. The other portion should move
forward for further lab testing for the protein
stability examination.

11. The above analysis will allow one to taste differ-
ent fining agent levels to help understand the
rate of bentonite added and the expected sen-
sory changes, if any, found at different levels.
Remember to incorporate an unfined sample in
your tastings and lab work as a reference point
to determine if a fining should be performed, at
all, on a certain wine.

12. If the wines are not settled enough for visual
examination one can employ the 0.45 micron
filter listed above to filter out suspended par- use the test tube holder or coffee cup.
ticles. If sensory is to be done after filtrations Remove the test tubes from the heat source and
make sure to treat the filter pads prior to use allow to cool to room temperature. Visually
with a light citric acid solution. This will remove

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