Diagnostic Key Mitigation of Post-Fermentation Off-Characters
Mitigation of Post-Fermentation Off-Characters
Many of the off-characters produced during aging are of a lasting nature and not easily removed from the wine. Small molecular weight volatiles may be removed from the wine using technologies such as reverse osmosis to remove components such as acetic acid. Spinning cone and other volatiles stripping techniques can also be applied but these may tend to strip the wine of desired components. If used correctly, these components can be recaptured and re-added to the wine.
Fining agents may also be used to remove undesired compounds, but fining trials should always be run on small samples of the wine to determine the impact of the treatment. Agents containing charcoal may be particularly effective but also have the strongest impact on overall aroma and flavor of the wine. Sometimes spent lees are used to remove components but this is not always effective as it depends upon the nature of the component and of the lees.
Blending may be used to reduce an offensive character to a level below its threshold of detection. This practice too must be employed with caution allowing a sufficient marrying period to determine if the compound is indeed below its threshold versus being in an altered chemical state that will eventually return to the aromatic form. Masking is sometimes also employed or considered the idea being that a strong positive aroma will mask a low concentration of a negative one. Again depending upon how the two characters change during aging the negative character may reappear later during aging or after bottling of the wine.