Term
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Definition
Accelerate precipitation of suspended particles
stabilize wines against haze formation (protein haze)
eliminate off odors (sulfides, oxidized aromas)
remove astringent phenolics, remove oxidized compounds |
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Term
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Definition
It is an aid and should only be used if necessary
fining agents are not highly specific
vineyard and winemaking "adjustments" can minimize need for fining operations (must nutrient, oxidation prevention, extraction during ferment) |
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Term
| General Principals behind fining |
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Definition
| based on electrostatic or hydrophobic interactions (rarely covalent) |
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Term
| Tannin-Protein Interactions |
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Definition
hydrogen bonds and hydrophobic interactions
hydrogen bonds between phenolic hydroxyl group and peptide bonds of proteins
reversible
dependent on tannin size, structure and charge
pH influenced (higher pH more charged Flavanol) |
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Term
| Categories of Fining Agents |
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Definition
Protein: gelatin, isinglass, casein, albumen
Carbons: Activated carbon
Synthetic: PVPP
Earths: Bentonite |
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Term
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Definition
amino acid composition, structure, size and charge play a role,
high proline content has an affinity for tannins
proteins usually have a + charge at 3.5pH
low temperatures favor precipitation
in general more protein=less tannins, but not linear |
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Term
| Protein Effect on Phenolics |
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Definition
-minimal decrease in color
-mainly effects larger tannins such as condensed tannins due to larger charge density
-minimal removal of smaller MW phenolics |
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Term
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Definition
produced from pig skins and animal bones
high proline content
positively charged
preferentially binds to larger molecules-
good to remove astringency
may be too agressive and make thin, bitter, hard wine |
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Term
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Definition
absorbs negativley charged particles as it settles
removes oxidized color and aroma, removed bittering compounds |
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Term
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Definition
sturgeon bladder, collagen based
removes tannin, phenols, color and yeast as well as general clarification of white wines
sometimes used to aid riddling
gentle fining, less tannins removed |
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Term
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Definition
gentle, polishing fining agent for reds,
3-8 whites per barrel |
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Term
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Definition
ox blood, used to reduce tannins,
no longer common |
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Term
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Definition
works by physical absorbtion
steam activated can remove off odors like H2S and ethyl acetate
can be too powerful
acid activated can decolorize wine
-dirty, hard to handle and nonselective |
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Term
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Definition
binds specifically with low MW polyphenols
insoluble- polyphenols absorb onto surface and precipitate
minimizes aroma stripping
used for removal of color, bitterness and some oxidized flavors
can be used to teat botrytis infected grapes with bentonite |
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Term
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Definition
binds specifically with low MW polyphenols
insoluble- polyphenols absorb onto surface and precipitate
minimizes aroma stripping
used for removal of color, bitterness and some oxidized flavors
can be used to teat botrytis infected grapes with bentonite |
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Term
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Definition
Claylike material, hydrated Aluminum Silicate
works by electrostatic interactions
large surface area for - charge
must be hydrated
protein stability, clarification, removal of oxidized color and aroma (due to rot) |
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Term
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Definition
combines with H2S and mercaptans and drops out of solution
(does NOT get disulfides)
may remove desired thiols
legal limit, .5mg/L copper ion |
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