Q: Conversion rate for fermentation?

Question from Karen: I have a question for you… If you crush wine grapes and the juice has 20% sugar, is the alcohol 5%??? Looking forward to your answer. Thank you.

Reply: Hi, Karen! Thanks for writing!

Here’s a brief reply from our winemaker, Geoff Gorsuch: Depending on all the parameters, yeast, temperature, nutrients, and how the crush and pre-fermentation treatment is handled you should end up around 9-12% alcohol if fermentation is finished.” By finished, he means if you let the wine ferment dry rather than stopping it in order to retain some sweetness.

The most common conversion rate of sugar to alcohol is 50-60% and Geoff allowed for a little more than that. The choice of yeast is one of the biggest factors and late-model, “cleaned up” yeasts are playing a role in the whole “hang-time” discussion regarding the alcohol in the finished wine.

Here’s how Wikipedia explains fermentation. Hope that helps! Cheers!

Q: Sulfites/California Wine/Headaches

Question from Susan: We have a friend who claims that she can only drink French reds because California reds have more nitrates/nitrites and give her headaches. Is this possible or is it a bit of wine snobbery?

Reply: Hi, Susan! Thanks for writing! I think your friend must have meant sulfites rather than nitrites. I’m pretty confident that nitrites aren’t a significant part of the wine picture (although they’re found in water, so…). They’re used to preserve hot dogs and salami and stuff like that. The sulfite question comes up pretty frequently.

It’s hard to blame her for thinking that French wine doesn’t have sulfites because, up to quite recently, only the US and Australia required the sulfite warning on the label. If you vacationed in Paris and drank French wine, a few years back, you wouldn’t have seen the warning. But, now you would (unless it’s an old vintage) and this applies to all the wine-producing countries in the European Union.

The law is very similar to the American one and enologists have determined that a bottle of French or California wine is likely to have around 80 parts per million. Any variation is more from brand to brand than country to country. Goosecross wine usually leaves here at around 30-35 ppm.

Sulfites, or sulfur, have been used to preserve wine for centuries. Even in Roman times it was used to help create a seal for the container. Without a little sulfur the wine loses its fruit and has a short shelf life. Fortunately, if the wine spoils it’s not harmful, but it’s not much fun to drink, either, which is why sulfur is still in use. Sulfites turn up in a lot of foods, too, especially dried fruit.

At this very moment, enologists are working to try to eliminate the need for sulfur. The success, so far, is by way of reducing it. Today’s wine has much lower sulfur levels than wine did as recently as 50 or 60 years ago.

This isn’t to say that you can’t buy wine that doesn’t have added sulfites. The “Organic Wine” designation prohibits sulfur additions to wine, as opposed to “organically grown”, which only refers to the farming (and even there, elemental sulfur application to the vines is permitted to keep mildew under control). The reason you don’t see very many “organic wines” is that they usually don’t taste very good. I should add that organic wine may still contain sulfites because they’re a by-product of the fermentation. The level, in that case, is extremely low.

As to the headaches, chemists keep telling us that sulfites don’t cause headaches, but statements like that can set off a maelstrom of heated opposition from those who believe otherwise. Your friend might try eating some brightly colored dried fruit to see if that causes a headache. If not, something other than sulfur is the cause. California wine is quite often higher in alcohol than French wine, due to climatic differences, so that’s the more likely culprit.

I hope that puts your debate to rest! May you and your friends enjoy wine, whatever its nationality, in good health! Cheers! Nancy

Q: White Zin/Red Zin: The Confusion Continues…

Question from Linda: I am still confused. Is white zinfandel considered a red wine and does it have the benefits I keep reading about red wine?

Reply: Hi, Linda. Thanks for writing! It seems that confusion about white/red Zin is extremely common, as I look through our “Ask the Educator” archives! So, here goes:

Even though White Zin is pink, it’s really made and tastes very much like a slightly sweet white wine. If I was categorizing it on a restaurant wine list, I’d call it a blush or pale rosé. If given only the choice of red or white, it’s most like a white.

It’s safe to assume that rosé wines have been made as long as there’s been wine but, as the story goes, the original, slightly sweet wine we call White Zinfandel was first made, unintentionally, at Sutter Home winery and it was this serendipitous event that transformed our neighbors from a very small farmhouse of a winery, into the multi-million case producer they are today.

Regarding the health benefits: Since the goodies (polyphenols, resveratrol, procyanidins) you’ve been reading about come from the grape skins it stands to reason that White Zin will be low in them because of the very brief skin-to-juice contact time it takes to get the light pink color (the juice of dark varieties is clear). Just the time it takes to get the fresh grapes crushed, stemmed and plopped into a fermentation tank can be enough, depending on the variety, state of ripeness and how much color the winemaker is looking for.  So I’d say that drinking dark red wine, in moderation, is more likely to provide those health benefits you’re asking about than pink or white wines. Any enologists or physicians out there care to comment?

If you’re not fond of red wine, but would like to be, there’s a fairly painless, but slow, way to develop a taste for it. If you’re drinking mainly White Zin and other sweet-ish wines, try a very fruity, but dry, white like our dry Viognier, or a dry Riesling or dry Gewürztraminer (you need to specify “dry” because these varieties are often made sweet). The fruitiness helps to bridge the gap from sweet to dry. Also, breaking in new styles goes easier if you include food – I’m always hungry Once you’ve come to a place where you like these dry wines, try something a little bigger, such as a relatively fruity Chardonnay (Goosecross Chard has loads of fruit). From there, go on to light-bodied reds like Pinot Noir or a Beaujolais type. A couple of days ago I served our sleek AmerItal Red blend to someone who said the reds are “too bitey” for her and she loved it. Before you know it, you’ll be asking for monster Cabs! It just takes a bit of time, and most of us prefer reds with a meal or some cheese (semi-hard to hard cheeses are usually best with reds).

I hope that answers your question and that you have a lot of fun exploring until you find something you really like! And, as always, when you’re contemplating drinking wine for the health benefitss, consult your physician! Cheers!

Q: White Zin/Red Zin

Question from Richard: I was recently informed that white zin is always red, is this correct? Is that a shortened form of white zinfandel?

Reply: Hi, Richard! Thanks for writing! There’s so much confusion about Zinfandel, White Zin (yes, Zin is short for Zinfandel – maybe also a term of endearment) – and blush! Not to mention blush vs. rosé.  Who can blame you, if you come to the conclusion that the industry goal is to make this as confusing as possible!

Here’s how it goes:

• If it’s called Zinfandel, or Zin, it should be red. There are those who assume it’s pale pink because they’ve only been exposed to White Zinfandel before but, if the name Zinfandel isn’t qualified in any way, you should expect a dry, red wine.
• If it’s called White Zinfandel, or White Zin, it will actually be light pink! Very confusing! Zinfandel is a dark-skinned grape with clear juice (like most red wine varieties) and the amount of color in the wine depends upon how long the juice is in contact with the skins. The length of skin to juice contact also has a big influence on flavor and texture. When making White Zin, most winemakers extract just a blush of color from the skins and thereafter the wine is produced as a white wine. Quite often they blend in very fruity white varieties, such as Riesling or Muscat, to accentuate the fruitiness. This will usually be sweet or sweetish.
• If it’s called blush, the wine has been produced just like White Zin, but using a different variety or a blend of varieties. If a variety is named on the label, like Merlot, then federal law is the wine must be at least 75% of the stated variety. If no variety is mentioned, you can assume it’s a blend.  Blush, also, tends to be sweet.
• If it’s called rosé, it may be a little darker than blush, but not necessarily (rosé means pink, in French). It’s often dry, but may be a little sweet. Really, blush is just a term that came into use to try to sell rosé at a time it wasn’t popular.

So, if you come into our tasting room – and I hope you do – and ask for Zinfandel, we will sadly tell you that we’re sold out of that delicious red wine at the moment. If you ask for White Zin or White Zinfandel, we’ll apologize that we don’t make any, but we do have a Merlot Rosé that’s just a tiny bit sweet: “ would you like to try that?” And, a few of our good neighbors make White Zin. That’s a long answer to a short question, but I hope it’s helpful!

Thanks, again, for writing and I hope you have wonderful holidays that include some equally wonderful wines!

Cheers!
Nancy

Does French Wine Have Less Alcohol Than California Wine?

Question from Dave: I always thought that the level of alcohol in a wine is dictated by the amount of sugar in the grape. Basically if you are producing a dry wine doesn’t the amount of sugar in the grapes dictate the percent of alcohol? I ask this because the wines in France are all in the 12 to 13 percent range. Is it because they harvest earlier not letting the sugar level in the grape get higher? Thanks, Dave

Reply: Hi, Dave! Thanks for writing! You are absolutely right. The alcohol moves with the sugar for dry table wines.

The main force at work here is climate. Here in sunny Napa Valley, when we complain, it’s often because there have been too many warm days. Heat sends the grape-sugar up and the acid down. On hot years the sugar may rise faster than the flavor matures. Since winemakers place a high value on flavor maturity, they may decide to wait for flavor development knowing that the resulting alcohol is likely to be a little higher than they wish (too much alcohol may feel hot on the palate and overwhelm the fruity aromas). That’s why the last three vintages have been such a blessing. The weather has been mild. Some viticulture professors believe that this may be the beginning of a trend, oddly enough, due to global warming.

In France, and other famous European growing regions, the more common concern is lack of heat and the threat of rain. Their warm years are usually the best ones (recently 2003, 2005). Some regions permit sugar additions (regulated by the local wine laws) in order to bring the alcohol up (if the alcohol isn’t high enough the wine may lack body and won’t feel satisfying on the palate). Many regions have established minimum alcohol levels in order to qualify for AOC status, or the equivalent for their country. They worry about high acidity, we worry about low acidity. So, climate change is working in their favor, too. They’re even expanding the wine-grape plantings in southern England, believe it or not!

So, that’s a long answer to a short question, but I hope it helps. Cheers! Nancy

NVWR® 57 – Top 5 questions for “Ask our Educator”

In this episode Nancy Hawks Miller, 25-year veteran of the wine industry and our Director of Education, takes on the top-5 most frequently asked questions in our online feature, “Ask our Educator“.

Podcast: Play in new window | Download

Q: How High can the Alcohol Get?

Question from Caryll: My father, husband and I have been discussing what is maximum possible alcoholic content in non-fortified wine. Not sherry, port madeira etc. I have noticed the creeping increase in alcoholic content and have preferred the French wines, which until recently hovered around 12%. I seem to recall wines which reached almost 17% but my husband says he thinks that it is impossible to make a wine of more than 14.9%. Help please! And if you could explain why as well…

Reply: Hi, Caryll! Thanks for writing! I swiped this quote from The Winemaking Page: “Nothing about wine is more lasting – or astonishing – than fermentation.” Matt Kramer, Making Sense of Wine.

It’s true that most wild yeasts have a very low alcohol tolerance, often dying off at 5% or less. They say that if you collect grape samples from vines anywhere in the world and analyze the juice, you’d find numerous strains of yeast, some helpful, others not. That’s why we know wine was discovered by mistake.

It wasn’t until the 1800′s that we realized that yeast is responsible for fermentation and, since then, we’ve gotten better at isolating the helpful yeasts. These days most of the world’s wine and beer is fermented with a yeast species called saccharomyces cerevisiae. Quoting Jancis Robinson, it “evolved from ancestral yeast by a process of genome duplication, rearrangements and deletions, estimated to have occurred over the past 100 million years.” Within the species there are several hundred strains with differing characteristics. One of the species’ distinguishing characteristics is very good alcohol tolerance and, as you pointed out, that becomes important when the alcohols start to creep up as they have in recent years.

You can see on this page that, depending upon which yeast the winemaker purchases, there is more or less alcohol tolerance depending upon which yeast strain is selected. Some of these yeasts tolerate upwards of 15% alcohol as a matter of routine.

Winemakers select yeast first for practical considerations, such as lack of off-flavor, heat or cold tolerance, performing well in a barrel vs. a tank, settling nicely when the fermentation is over and, of course, alcohol tolerance. But the science has advanced to the point that certain yeasts are chosen for contributing to flavor or accentuating certain varietal characteristics.

“Wild” or “native” fermentation, in which no yeast is added, is usually a mix of yeasts that inevitably include saccharomyces cerevisiae if wine has been made on the site before. It works its way into the vineyard and becomes part of the winery and is, most likely, the yeast that ultimately gets the job done.

Your husband’s idea that the wine can’t be higher than 14.9% may have something to do with wine tax laws. We’re certainly allowed to produce high-alcohol wines, but when we go over 14% we are taxed as if we made a fortified wine, to which the alcohol is added, and our $1.07 per gallon federal tax goes up to $1.57.

I hope that helps settle your family debate. For everything and more that you might want to learn about yeast, grab a glass of wine and try going to this page.

Cheers! Nancy