Making white wine.
One of the most basic elements of winemaking is the difference in techniques used to make white, rose, and red wines.
The basic recipe for making wines is pretty simple:
Leave fruit to undergo alcoholic fermentation, which converts sugar to alcohol
Allow wine to clear.
Take a nap.
Ok, now that we got that out of the way let’s take a closer look at this seemingly simple process.
We’ll begin with the making of white wine. White wine can be made from almost any grape. Even the vast majority of red grapes only have pigments in the skin so if the grapes are crushed and the juice immediately separated from these pigment rich skins, the resulting wine will be what we refer to as white wine!
Once a clear, or nearly clear juice is obtained from the grapes the alcoholic fermentation process can begin. In many instances today’s wines are fermented using cultivated yeasts, as these tend to produce more predictable and consistent fermentations, and results. Of course, traditionally the juice was fermenting using the yeasts found on the grape skins, the so-called indigenous yeasts.
Once the fermentation gets going and the yeast cells are eating up the sugar they produce three by products, alcohol, carbon dioxide, and heat. The alcohol we know all about and are hoping for, the CO2 I’ll touch on later but can be a very good thing for the wines, but the heat, well the heat can be a problem.
If the fermenting must, that’s the roiling mass of juice and yeast cells in this case, gets too warm, the resultant wine risks losing it’s freshness and appealingly fruity character. In order to preserve this bright, fruity quality the temperature of a wine’s fermentation is strictly controlled. A long, slow, cool fermentation is generally the goal with white wines. Typically it only takes a few weeks to complete this cool fermentation.
The wine is ready to be racked once all the sugar has been converted to alcohol, and frequently just before, as a tiny touch of RS or residual sugar, that is the sugar that has not been converted to alcohol and has been left in the wine, tends to make a wine feel lush and seem fruitier to the drinker without being noticeable sweet.
Racking simply means that the juice is drawn off the solids, tiny bits of grape flesh and dead yeast cells that are allowed to fall to the bottom of the barrel, So the wine is racked into new, clean vessels to remove the lees, those bits of solids, from the wine. This racking may be repeated as the wine continues to clarify, but some wines are left on these lees. The winemakers leave the wine on he lees, and actually stir the lees to increase contact with the wine, as these solids can add complexity and richness to a white wine.
The type of ageing vessel is fundamental to the style of wine the winemaker is hoping for. Classic, buttery Chardonnays are not only fermented in small oak barrels, but generally are aged for months on their lees in these barrels. Lighter, fruitier whites such as New Zealand Sauvignon Blanc and Italian Pinot Grigio usually are only exposed to neutral stainless steel vessels to help preserve the fresh, aromatic character of these wines.
While wine has traditionally been made in synch with the seasons, modern innovations have affected this cyclical timing. Case in point: Malolactic fermentation.
In the traditional wine making cycle the grapes were harvested as the fall cooled then underwent fermentation in a cold cellar, generating enough heat to keep the yeast cells happy. Once the yeast cells died and fermentation ceased the wine cooled to cellar temperature and was allowed to clarify naturally as the lees precipitated out of the wine and fell naturally to the bottom of the barrel. Once the cellar began to warm the following spring the last element of the winemaking cycle began, the Malolactic fermentation.
During the malolactic fermentation hard and aggressive Malic Acids, those found in green apples for example, are converted into softer, creamer Lactic Acids, those found in milk and cheese. Not all white wine undergoes “malo” but those that do are left with a softer feel and tend to have a pronounced buttery element.
Of course all of these steps can, and frequently are, taken in rapid succession with the wine filtered immediately after fermentation. Frequently wines undergo “cold stabilization” during which process the wine is chilled to almost freezing so that excess tartaric acid crystallizes and falls out of suspension. The wine can then easily be warmed sufficiently and inoculated with the proper bacteria to get the malo-lactic fermentation started.
By taking these steps a natural cycle that may take 6-8 months to complete can be achieved in a matter of weeks.
And that brings us to the final steps of producing a wine for sale. The bottling. One element of the bottling that has been brought to the fore over recent years is the fact that sulfites are added to wine during this step to act as a preservative. While very low levels of sulfites are created naturally during the fermentation process, adding sulfites throughout the winemaking process has been a technique used to prevent bacterial spoilage and the premature oxidation, or ageing, of wine for millennia.
The problem with high levels of sulfites is that some people are allergic to them, suffering from painful reactions, in particular impaired breathing and rashes. Today’s wines can be made with far lower levels of sulfites than were used in the past since modern winemakers are much more aware of the role hygiene plays in keeping bacteria and undesirable yeasts at bay. In addition, if you recall, there was carbon dioxide produced during the fermentation process. By trapping that CO2 in the wine, wine-makers have harnessed the anti-oxidative properties of the dissolved gas and are able to use it to replace most or all of the sulfites they used to add. Of course the trade off may be a slight spritz to the wine when it is first opened but that is quickly remedied by giving the bottles a set of vigorous shakes!
Well those are the basic steps in the production of white wines. There are variations that allow the winemaker to produce rose and red wines but I’ll touch on those in another post. This seems more than enough to digest!
The Winemaking Process
- Reply by Babsomatic, Aug 19, 2009.
Pretty good write up. I work at a winery and am still a newbie on the production side, but that was well done!
- Reply by Gregory Dal Piaz, Aug 19, 2009.
Thanks very much!
Where are you working?
Would love to know what's going on with you.
- Reply by gpascazio, Aug 22, 2009.
I have a question regarding the addition of sulfites to wine. My understanding is that the adding of sulfites to wine is mandated by the US government, is this true? My reason for asking is that we where in Italy this spring and the wine there tastes different, much better. What's the difference? Is it the sulfites? In addition the Italian wine that I drink here in the US does taste as good. Is it becouse things taste better on vacation or is it the sulfites?
- Reply by Gregory Dal Piaz, Aug 22, 2009.
Sulfite addition is not mandated, and in fact the number of producer trying to produce no sulfite added wines is increasing, although with very varied results.
it's impossible to compare wines from Italy, say, with wines from California in a general way. Italy produces many more grape varieties and has a much more varied set of geological and climate combination so that from Italy you can find everything from high altitude cold climate vineyards to hot fertile plains packed with vines.
In general what you can say is that Italian wines tend to have higher acidity than many others and are generally less oaky, particularly at the lower price points, which is what most Italians drink. It just may be that you prefer Italian wines, as i do, because of these factors.
And besides it's a fact that everything tastes better on vacation.
- Reply by happyrobot, Aug 23, 2009.
Three was an interesting article about sulfites that I had bookmarked back when I was doing the WSET program....
"…all wines contain sulfites. Yeast naturally produces sulfites during fermentation so there is only a rare wine which contains none"
- Reply by happyrobot, Aug 23, 2009.
Oh, and Gregory. Nice write-up!
- Reply by gpascazio, Aug 23, 2009.
Thank you both for the reply, Gregory and happyrobot, I definitely learned something. I also would like to thank you Gregory for your original post on the winemaking process.