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Archive for the ‘Answers to Your Technical Questions’ Category

Tartrates – those glass-looking things at the bottom of my Chardonnay

Posted by Genevieve Rodgers-Llerena on January 10, 2008

So there you are, you’ve just cooked this amazing gourmet meal for your close friends who, like yourself, happen to be HUGE wine fans. Everything is prepared, the apps are ready, the table is set, and you’ve anticipated every eventuality. Knowing that your friends are due to arrive in five minutes, you reach into the fridge to pull out this great white wine you found at an out of the way winery in Healdsburg only to find it not there. Looking around you spy it on the counter – it’s warm. But, thinking quickly, you open up the freezer and stuff it in the ice tray. No problem. That is until you take it out and find that your boutique white wine now has little grains of glass-looking crystals floating in your bottle. Does this sound familiar?

When this happens to you, the key is Don’t Panic! There is no cause for alarm. The crystals are tartrates that were happy enough to be soluble at room temperature, but not so soluble at the low temperature of the freezer. The crystals are generally caused from tartrates precipitating out of the wine at cold temperatures. Tartaric acid is naturally found in grape juice, as are tartaric salts – Potassium bi-tartrate and Calcium tartrate. They are part of what makes wine wine. Unfortunately, these tartrates are not very soluble at higher alcohols and lower temperatures.

So, how does this happen? When the wine is chilled, some of the acid and salts become insoluble and form small crystals. Sometimes, when the crystals link and grow, they look almost like glass shards. The crystals may float in the wine, fall to the bottom of the bottle, or attach themselves to the cork. Please note: they pose NO HAZARD, nor do they change the taste or smell of the wine. Usually this occurs in white wines and is rare in reds. Most wineries will subject the wines to very cold temperatures before bottling to encourage the crystals to drop out of the wine in the tank. When wines are cold stabilized in this way the crystals will generally, but not always, be inhibited in the bottle. The chillers necessary to cold stabilize wine are quite expensive so small boutique wineries may not be able to invest in them and so may have a higher incidence of crystal formation. Also, wines that are unfiltered and unfined may have more crystal formation. Besides large changes in temperature, age can cause tartrates to precipitate into the bottle

If you notice a particular wine has a lot of crystals in it, try not chilling it as cold. This will mitigate the amount of crystals. Let your bottle rest upright for a while to let these crystals fall to the bottom. Pour your wine, carefully leaving the last bit of wine in the bottom of the bottle, along with the crunchies, and, enjoy! These boutique and small production wines may not always look as pretty, but they make up for it in the unique flavors that are a result of the artistry.

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Yeast, Yeast, and More Yeast!

Posted by Genevieve Rodgers-Llerena on October 29, 2007

Yeasts are really the unsung heros of our civilization. Without yeast there would be no wine – perish the thought – only grape juice. There would be no cider, no beer, no vinegar (it’s a derivative of the three aforementioned beverages), no bread, no pizza, and the list goes on. I think you could make a case that there indeed would be no professional sports. Sure high school and college sports would not be gravely affected, but if I’m going to pay to see grown men (who make more money in a year than most people will ever see in a life-time) kick, hit or pass a ball around, I want – no need – a beer. Pizza is a close second. Really life as we know it would be radically different without the humble yeast.

 

yeast

So, what do yeasts really do? Here’s the simplified version: Yeasts breakdown (will call it eat) sugar and nutrients and produce alcohol, carbon dioxide, volatile metabolites, heat and more yeasts. They are the vital ingredient for turning grape juice into wine. It’s easy to point to alcohol production as the key byproduct of yeast activity, which is exactly what the government does. But you would be missing one of the yeast’s most amazing accomplishments – volatile metabolites. These are the esters, sulfur compounds and volatile fatty acids that make wine more flavorful than the grape juice it is derived from. No one sits around with friends expounding on the wonderful mouth-feel and aroma of grape juice; but there are thousands of websites devoted to those aspects of wine. Many of the compounds that give wine its flavor, aroma, color and mouth-feel are released or modified by the yeast during fermentation.

Wine makers choose yeast based a variety of attributes. The first thing a winemaker does is determine which yeasts are suitable for the wines that she is making. Yeast strains have been isolated to compliment different grape varietals, because of the different volatile metabolites that they create, and their ability to ferment in varying levels of alcohol and temperatures. Next a winemaker needs to determine what qualities should be enhanced or reduced in the wine. For example, a winemaker making Cabernet Sauvignon may choose BDX (Bordeaux Red) if she is worried about color loss or to enhance aromas. If the Cab had to be picked a little earlier than optimal, or if it has nice spicy aromas, she might pick CSM instead. Personally, I like to break up the fruit into two or more lots and use different yeasts in each tank. This way I can develop more complexity in the finished wine when the tanks are blended together. I get most of my yeast from Vinquiry as they have a nice selection. Here’s the link if you want to know more about available yeasts http://www.vinquiry.com/pdf/YeastDescription0607.pdf .

 

I would be remiss if I didn’t also mention the natural, or native yeast, fermentation method. Many wineries are using this method for fermentation, and while it may seem Nouveau, it has been used for several millennia. For a natural fermentation the wine is not inoculated with a commercial yeast, hence the name natural. The winemaker allows the yeasts that are present on the fruit to carry out the fermentation. On the surface this sounds like a very straightforward and simple way to make wine. It’s very inexpensive and after all isn’t this the way wine has been made for thousands of years? Well yes, BUT… When wine is inoculated with a commercial yeast, that yeast dominates the fermentation from the very beginning to the very end. They have been isolated because they are hardy in very inhospitable environments, when the must is at low temperatures and high in sugar and when the must is at high temperatures and high in alcohol, and also because they produce flavors and aromas that are pleasing. During a natural fermentation yeasts of several different genera are active with different types of yeasts dominating during different stages of the fermentation process. The hope is that in this mix of yeasts there are those that hardy both at the start, in high sugar, and at the end, in high alcohol, and that they produce a wine that is pleasing. But, there is no guarantee that this will be the case. And, there are few things more terrifying than a fermentation that stops before the wine is dry. This is where the winemaker earns her keep.

So there you have it, a very brief introduction to yeast. Please remember them when next you have a glass of wine, or a slice of pizza.

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Rain? Yikes!

Posted by oenophilus on October 10, 2007

Genevieve & I were minding our own business last night, sipping a gorgeous artisan red vermouth on the rocks, watching the brilliance of Hugh Laurie on House, when she asked the question that every winemaker and winegrower dreads hearing during Harvest. “Is that rain?” Yes, indeed-ee, Ma’am. It was pouring down like it hadn’t rained hard for months….Wait. It hadn’t rained hard for months. We have had the traditional Northern California dry summer, right after a very dry winter. It was time for a good rain.

Unfortunately, many growers still have fruit on the vine. Usually by the time the first hard rain hits, most of us have picked our grapes, gotten them through their first fermentation, and had them safely tucked away for their “long winter’s nap.” How does this affect the grapes? How does this affect the wines yet to come? Well that comes with more Depends than a keg party at the Old Soldiers’ Home.

Depends on what? When we are patiently waiting for wine grapes to finish ripening, we are waiting for a number of factors: flavors, acids, sugars, and pickers. Rain can adversely affect all of these factors. The plant sucking up a lot more water will cause the grapes to swell, thinning their skins. Rain will also dilute flavors, lower sugar levels, lower acid levels, and make it very hard to pick the fruit. Is that the end of the great wine the vintner had planned on making? Depends. Maybe the sugars were already too high and the plant can process the water, restore the flavors and balance the acids before the sugars soar again. How fast can pickers get into the vineyard so the plants don’t move all the water into the fruit? Depends. If you had a lot of rain on a very steep clay slope, the pickers can’t safely climb up and down the hill until the ground dries out. If your vineyard is on a valley floor, it may be prone to flooding and the tractors following the pickers can’t get in to haul the fruit out. If you have a small vineyard and rely on a vineyard management company to pick for you, guess whose phone was ringing off the hook last night and early this morning for every client left to get picked? Whole lotta Depends here. Noble Rot

Another extremely important factor is mold and rot. Sweet grapes have already attracted all sorts of creepy spores that are just waiting for conditions to be right to them to populate, grow, and do the nasty on your PHAT bunches of grapes. What are the right conditions? Wet, warmish, still air, tight bunches, thin skins, and a little time all contribute to grapes rotting away. You don’t need a CSI team ducking under yellow tape to analyze this. These grapes look and smell Yucky! You wouldn’t want to get these anywhere near your mouth. In a very small number of select instances, the dominant fungus will be Botrytis Cinerea as “Noble Rot”. In some varietals, this will produce magical flavors that drive many of us to a maddened neurotic passion that is brought on by the great dessert wines resulting from a proper handling of this icky fruit. If you are not already a convert, you MUST try Sauternes, Baumes de Venise, Tokay Aszu, Trokenbeerenauslese, Amarone, and a new bunch of late harvest or “Botrysized” dessert wines from North America.

For the most part, winegrowers are working themselves into a frenzy today and winemakers are getting ready for fruit. We are all watching the weather to hope that we get a strong breeze to dry out the grape bunches. We also hope that it gets hot and sunny enough to speed things along, not just gets warm and humid to make the rot spores feel right at home. Is the 2007 vintage in danger? Get real. We are SO past the days of stuffed-shirt pundits making broad swath declarations of quality that have no meaning on reality. Every Grower and Vintner will do their best with what they are given to get you the best wine that they can possibly make. Let’s wait to unscrew some caps and pop some corks in a couple of years to see what the Rains of October 9, 2007 meant to Northern California wine country.

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Is It Time to Pick Yet?

Posted by Genevieve Rodgers-Llerena on September 17, 2007

Ah, September! Wineries are running at full steam. Winemakers and their crews are wondering when they’ll get some sleep. And growers? They are biting their nails – praying to the gods of good weather. It’s Harvest Time in the Wine Country! This is the time when a lot of the good stuff happens. Water gets turned into wine. So the pressing (wine pun) question is: how do you know when to pick?

Really, picking is one of the biggest decisions a winemaker will make…and it’s a complicated one. As a winemaker, my job is to get the absolutely best grapes possible, but it’s not the only consideration. Upcoming weather can be a huge factor: a hard rain or a week of heat above 100 degrees can destroy otherwise perfect grapes. Then there’s making sure I can get a picking crew and an empty tank – easier in the beginning of the harvest than at the end. Let’s pretend for a moment that the weather is perfect, crews are plentiful and empty fermentation tanks abound….

Judging when to pick starts with a walk in the vineyard. A healthy vineyard will allow for better and more even ripening. I can pick out trouble spots that may need more care. Uneven ripening may throw off the ever important sample. It seems that every winemaker has a different method for sampling a vineyard – but, I think mine’s best. I like to get a repeatable sample. It’s not truly a random representation like they taught in winemaker school. But this way I can use yearly data to correlate readings from year to year and so better manage the vineyard to get what I want from it. I pick four rows in each block and test the same rows every year. Each sample takes 5 berries from 5 vines from each four rows, taking berries from all sides of the cluster.

Once I have my 100 grapes (check my math: 5x5x4), I do a combination of qualitative and quantitative tests on the sample. I test three sets of three berries. I put each set in my mouth and feel the texture and taste of the pulp and the skins. I’m looking for the pulp texture to get really liquidy and separate easily from the skins. The taste goes from: vegetal to herbaceous to unripe to red fruit or green fruit to black fruit or tropical fruit and finally to jam. I’m looking for red or black fruit in a Cabernet, green or tropical fruit in a Chard. Sometimes I like a bit of jammy flavor in a Zin, but only a bit, as those flavors can lead to high alcohol wines which are not my style. The skins should start to fall apart when I chew them and should lose their bitterness while gaining the nice fruit flavors. The seeds should turn brown and get crunchy. I crush the rest of the sample in a nice ziplock bag and test the juice for sugar (Brix as % of sugar solids), pH (acid to alkaline scale) and TA (titratable acidity) if possible.

Ideally, I’m looking for white grapes to fit these parameters:Brix 22.5 – 24.5, pH 3.2 -3.6, TA 0.65 – 0.75.  I like Red grapes closer to: Brix 24.5 – 25.5, pH 3.4 – 3.8, TA 0.58 – 0.7.

The big question: Which is more important, the taste or the numbers? A loaded question gets a loaded answer. The taste and texture of the grapes are my first priority. You can’t make great wine from grapes that are bitter and taste like veggies. You also can’t make great wine from grapes that are way beyond the ideal numbers. In the end, I want the best tasting grapes that fall within my parameters. At that point I pray for good weather, a picking crew and space for the wine. Really? Making wine involves a lot of prayer, and even more beer. But that’s another blog altogether…

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