In the 18^th century, egg whites were used to clarify red wine

Turbidity, acidity, sourness, staleness, mould – wine faults were numerous in the Middle Ages. The long list of remedies includes some methods that have been lost to us today. We learn in household books from the 18th century that to make red wine clearer and to get rid of the lees, you should always add an egg white.

The reaction between the egg’s proteins and the tannins in red wine provoke precipitation. The impurities can thus be eliminated easily. The reaction also softens the wine and renders it more supple. The egg is, and remains today, a precious ally for vinification. Another solution is to toss in a good handful of well-washed sand. This method is still proving successful because Bentonite, a highly regarded clay, is currently used to clarify wine.

Other recipes have come to us down through the times, while some are simply no longer authorized. To overcome a stale taste, you can mix oxidized wine with a freshly pressed Muscat. To keep wine from turning to vinegar, you can leave the roots of a fern soaking in the cask. To cover up the taste of mould, add very ripe medlar fruit to pump out the bad taste. Also suggested: add a few drops of essence of violet, anise, cinnamon or flower of cloves to a bottle of wine just before serving it.

Sourced from
BUCHARD Cristina, CLAVIEN Corinne, « Recettes et savoir-faire pour bonifier le vin » in Histoire de la Vigne et du Vin en Valais : des origines à nos jours, Sierre-Salgesch, Musée valaisan de la Vigne et du Vin, Gollion, Infolio, 2009.