The Auswine Forum

Hi all I am curious if anyone knows why most wine labels say contains traces of skim Milk or Egg Whites or yeast? Obviousley because they contain it from somewhere along the winemaking process but why would this be? At what stage would they use it and for what bennifits? Wonder how much is used.

Yeast is used in fermentation to make the wine, egg whites and I think casein from milk are used as fining agents to clarify the wine by removing small particles of solids remaining from the winemaking process. If the wine is not heavily filtered then traces of any/all of these may remain in tiny quantities.

I Did not know wine had yeast i thought it was only beer. Are they the same type of yeasts. How much do they put in?

Anonymous wrote:I Did not know wine had yeast i thought it was only beer. Are they the same type of yeasts. How much do they put in?

Wouldn't be wine without yeast. I have no idea of the specific amounts or strains used, but in general:

Making the alcohol from sugars is what these little yeasts do best, some wines are made with naturally occurring vineyard yeasts, but most are innoculated with a specific yeast culture for the type of grape, intended wine style, expected alcohol level etc. The yeast either dies when the alcohol level gets too high (what a way to suicide) or they are killed with sulphur dioxide. The sludge is removed by some/all of settling, racking, fining, filtering, disgorgement etc.

There won't be much yeast left in the wine (except for flavour in some bubblies that mature on the yeast lees (dead yeast), it's not regarded as a desirable flavour except in some champagne styles.

Anonymous wrote:I Did not know wine had yeast i thought it was only beer. Are they the same type of yeasts. How much do they put in?

Strains are generally Saccharomyces cerevisiae, some bayanus strains are used. These are the same genera as beer yeast, however the strains are very different in terms of fermentative capacity.

Generally a fermentation is inoculated with about 5 mill. cells, where culture density reaches up to 5 bill cells.

Uninoculated fermentations are a completely different kettle of fish.

Yeast lees is actually used a lot more than just Champagne style of wines, it plays a large influence in most styles of winemaking, be it for reductivity or flavour/textural component, amongst other things.

Quantities of fining agents are typically very low, in the ppm range. Most are proteinaceous in property, consequently form colloidal masses and precipitate larger compounds, like tannins etc...

Sorry, that was me.

Cheers,
Colin.

There is a little more on what can be used in fining here and here.

Note. The stated goverment approvals (BATF) apply to USA.

Mike