C A T A L O G U E e n o l o g i c a l p r o d u c t s

Fining Agents
...About fining
Fining agents are materials that help remove undesirable
elements from wine. Fining is not just used as a clarification
technique to prepare wines for bottling, but can also be used
to modify several wine attributes that will lead to organoleptic
improvements and wine balance. Generally speaking, there are
more benefits from early fining rather than later in the life of a
wine. Early fining allows the wine to age properly, while limiting
further more aggressive treatments prior to bottling.
The purposes of fining:
• Clarification
• Stabilization against future haze and sediment formation
• Improving organoleptic properties
• Reducing astringency
• Reducing bitternes
• Removal of off-aromas
• Color improvement
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HOW DOES FINING WORK?
The mechanisms of action in fining are diverse and depend on
the nature of the fining agent. These interactions can be based
on charge, formation of chemical bonds, and/or absorption or
adsorption of compounds. When added to wine, fining agents
usually form a colloidal dispersion. Depending on the electrical
charge of the fining agent molecules when dispersed in wine,
the colloids may be classified as being either electropositive
(e.g. protein fining agents such as gelatins) or electronegative
(e.g. tannin, bentonite, silica sol). These interactions lead to the
formation of two important processes that need to happen in
sequence: first, flocculation (the aggregation of two or more
macromolecules) then sedimentation (when the flocculated
materials settle to the bottom of the tank).
Research on interactions between tannin and gelatin have shown
that other factors are important in flocculation and sedimentation.
FLOCCULATION AIDS (CO-FINING)
When fining white and rosé wines, some protein-based fining
agents (particularly gelatin and isinglass), which form colloids
with a positive electric charge, require the addition of negativelycharged
colloids in order to ensure complete flocculation and,
eventually, precipitation. Such negatively-charged flocculation aids
include: tannin, silica sol and bentonite. Bentonite can be used as
a co-fining agent for all protein fining agents. When fining with
gelatins or isinglass the best co-fining agents are silica sol or
tannins. (Tannins need to be added a day before fining)
EVALUATING THE PERFORMANCE OF FINING AGENTS
Trials are essential for evaluating the efficacy of a treatment. Fining
agents, as well as the concentration ranges used for a trial, should
be selected on the basis of the change that is desired in the wine.
It is important to test several rates and select the lowest dosage
needed to achieve the desired effect to avoid over-fining.
When particles with opposite electrical charges are attracted to
each other by electrostatic interaction, a dehydration phenomenon
takes place on the outer surface of the aggregated particles (or
micelles). The presence of Na + , K + , Ca 2+ , Mg 2+ and specially Fe 3+
cations is indispensable for this phenomenon to occur. This will
lead to hydrophobic interaction between the aggregated particles
which then leads to their precipitation.
Origin and charge
Proteins (+)
Earths (-)
Tannins (-)
Synthetic
compounds (-)
Table 1 Nature of fining agents
Material
Gelatin, casein, albumin, isinglass
Bentonite, silica sol
Ellagic tannins
PVPP, PVI-PVP
For fining trials intended to modify organoleptic properties
of wine, the most important test of all is a properly conducted
sensory evaluation of fined samples against an untreated control.
Additionally, there are several tests that winemakers can use to
cross reference with their sensory evaluation (see table 2).
Clarity
Color
Polyphenols
Filterability
Protein stability
Color stability
Overfining
Volume of lees
Turbidimeter or naked eye
Abs. 420,520, 620 nm
(color intensity, hue)
Abs. 280 nm
Fouling index and/or Vmax
Heat test
24 hrs at 0°C (32°F)
microscopic examination of sediment
Addition of tannin
Cone or cylinder
PREPARING FINING TRIALS
• Decant wine samples to desired volume, leaving space for
fining material to be added.
• Label each with sample identification and material addition
level. It is best to make additions as soon as possible after
decanting.
• Keep one bottle as a control.
• Use Table 3 for volume of material to add per 100 mL of
wine. IMPORTANT: Make the addition to wine sample and
mix immediately.
• Top off each bottle with wine, mix again. Make sure Control
bottle is topped off.
• Store at about 15°C (59°F) for settling, usually 1-2 days, until
samples are ready to be evaluated.
• Remove and let come to room temperature before evaluating.
g/hL 1% 3% 5% 10%
1 0.1 0.03 0.02 0.01
5 0.5 0.17 0.1 0.05
10 1 0.33 0.2 0.1
15 1.5 0.5 0.3 0.15
20 2 0.67 0.40 0.2
30 3 1.0 0.6 0.3
40 4 1.33 0.8 0.4
Table 3 Millilters of a fining agent (%) solution to add to 100 ml of wine