"True Facts" Filtered Controversy

Wanna start a fight with a winemaker? Just take a side on the filtering issue and you are guaranteed a feisty discussion. Magazine writers and wine reviewers fawn when they see “unfined, unfiltered” on a label, so it follows that consumers just accept a view that a filtered wine is therefore something less, having had aspects of a its aroma and palate filtered out. The best filtration is no filtration! But is that entirely true?



Filtration is a common practice in winemaking even if not everyone agrees on its necessity to create great wine. Some winemakers brag that their wines are unfiltered and therefore better. The argument goes that filtration can rob wine of desired qualities, such as taste and smell, leaving a wine that is clear to look at yet without character, and further justified with the mantra that wine should be manipulated as little as possible. Those braggarts tell us to believe that an unfiltered wine has more intense flavors, texture and aroma.

Let’s agree that when possible, wine should not be filtered.  The less a wine is needlessly tampered with, the better. Filtration by definition removes something; some character from a wine.  Some of this character invariably contributes to the texture and aromatics of a wine. Filtering also adds an additional step to the bottling process and increases the risk of oxidation as the wine goes from filtration to bottle.

Why Filter Then?

Filtration involves removing sediment, grape skins, dead yeast and other particles from wine by passing it through filter media that has (microscopic) holes big enough for the wine to pass through yet small enough to catch any floating particles. Judicious filtration removes yeast, microbes and other larger solids while still allowing the tiny molecules that are responsible for color, flavor and aroma to pass through the filters, allowing clarity and brilliance to be achieved. Using a filter properly does nothing but remove undesirable microorganisms and solids and should not have any major effect on flavor and aroma.

The experienced and pragmatic winemaker knows that there are serious risks involved in bottling a wine with an unknown load of bacteria and, perhaps, yeast. there are a significant number of wines on the shelves in retail stores with the telltale signs of post-bottling microbial growth. Filtering largely removes that risk and, therefore, it is often standard procedure.

Filtration makes a wine “brighter,” meaning clearer, and attractive to look through in the glass. Myself and most of the wine drinking community expect a wine to pour clear, not cloudy and opaque.  A winery may decide to filter for strictly this cosmetic reason.  But as previously said, a winery may decide not to filter their wines because they feel that too much of the wine is left on the filter media, and that the unfiltered wines taste better and have superior mouthfeel. 

To filter or not to filter involves compromises on both sides of the question. What I find from talking with many winemakers is that the filtration question becomes a philosophical, even emotional one rather than a practical one based on logic.
 
One could make a convincing argument that carefully made fine red wine that has been matured in barrel shouldn’t even need filtering.  Racked off after spending months in wood a wine should be stable against problems caused by protein and tartrates, as well as yeast and bacteria problems. By the time the winemaker has coarse filtered and fine filtered, the wine is already brilliant.


As a practical matter, in some cases filtering is an absolute necessity. Such as the case for any wines containing residual sugar. It could be entirely necessary for wines containing malic acid - to prevent malolactic fermentation in bottle. Similarly, wines intended for short-term consumption often don't have the acidity, or alcohol and tannin levels that offer resistance to biological instability. Wines made for ageability and to be cellared might be expected to have a little sediment after some years, but most consumers have little understanding or tolerance for the appearance of natural crystals and deposits in an early-drinking wine. 

This means that pretty much all white wines should probably be filtered to a sterile degree. For a red wine where absolutely no Brettanomyces influence is to be acceptable, then a winery really has to weigh filtration’s slight effect on mouthfeel against the chance that the wine will smell like a barnyard in a year or two. 


Winemakers and consumer should be cautious of building a philosophical argument on a practical issue like filtration. If you want the benefits of labeling your wine as unfiltered, you had better take the trouble to ensure that the wine you bottle contains no more than a minute quantity of viable cells, and that your customers won’t be put off by an opaque appearance or sediment. A balance of a low level of bacteria combined with a relatively high level of sulfur dioxide would be the aim for a wine that is not going to be filtered. 




What's Involved

Wineries use filtration systems with a series of different grades of pads (or cartridges). The process begins with the wine being filtered through coarse filter pads, then may continue undergoing a second "fine" filtration, using clarifying filter pads, followed by a third "polish" filtration, which can result in the wine taking on a brilliant clarity. A final step, "sterile" filtration, uses membrane filters that are fine enough to remove yeast cells, thus preventing further fermentation.

The sterile filters commonly used nowadays are usually a tight depth filter depth and then a membrane filter.

Sources: www.winebusiness.com, and Gary Baldwin - Australian wine consultant

"True Facts" Diamonds Aren't Enough

Diamonds (and wine!) are a girl’s best friend, but who’s friend are those “diamonds” IN your wine?

You see them as sparkly purple bits on the end of a wine cork or as crusty bits coating the sides of an empty wine glass. They appear like coarse sugar crystals or even as shards of glass when you pour out that last bit of Chardonnay. While not exactly appetizing or appealing, these bits of sediment aren’t UN-friendly. In fact their appearance is a sign of wine as a natural product.

Whether purple stained, creamy colored or clear, these crystals are called tartrates or potassium bitartrates. In your kitchen you will recognize this as an ingredient from your baking cabinet known as cream of tartar! In fact, the cream of tartar you use to stabilize egg whites for meringue is also in the baking powder that you use to make your muffins rise, and it was probably created as a byproduct of someone’s winemaking efforts.

Tartaric acid is the dominant acid in grapes/ wine and in the presence of potassium (it too is natural in wine) and cool temperatures this “salt” or crystalline form is precipitated. Cold temperatures can also be utilized to prevent the tartrates from forming in your bottle. Winemakers will chill vats or containers of wine (especially white) in a process called “cold stabilization” in order to force the creation of the tartrates so that the crystals can be filtered out prior to bottling.

Winemakers will take the extra steps to cold stabilize their wines simply because the uninitiated wine drinker may become alarmed by the crystals at the bottom of his/her bottle or glass. No need for alarm or concern! They are completely harmless and natural and they won’t poison you or slice up your tongue!

What about filtering? Some winemakers brag that their wines are unfiltered and therefore better. More about whether this true next week.

"True Facts" Corked?

What do you do with the wine cork when the waiter presents it to you? “Hurry up and pour the wine already, you pompous Dingbat, and take the garbage off of the table!”

(or not...)

If in fact the bottle you have chosen with dinner even comes with a cork (screwcaps are everywhere!), the practice of presenting the just-removed cork to the host is part of the ritual and tradition of fine wine service. For older bottles especially this practice makes good sense.

The Sommelier, Wine Steward or waiter will have inspected the cork themselves, looking for signs of seepage, mold or other abnormalities that could add up to a bottle full of vinegar rather than wine. Once removed from the bottle neck the cork may be presented to the host, or head of the table for inspection.

No, you aren’t supposed to smell it, though you may since it can offer a very pleasant scent. However, smelling the cork would tell you very little, if anything about the wine. Smell it if you want to AFTER the Sommelier goes back to his cellar, is my advice.

You may have seen corks that are stamped with the vintage and name and image of the Chateau or winery, and this is one thing you might look for when the cork is placed in front of you. More than a century ago when the phylloxera scourge reduced the grape harvests in Old Europe, wine fraud was not uncommon. An unscrupulous merchant could refill a real bottle or slap a fake label on a wine in a bottle from anywhere and attempt to pass it off as genuine. Seeing that the cork is authentic and true was one guarantee of authenticity.

A still contemporary reason for you to at least look at the cork is to check whether it is brittle or unusually dry. For aged wine this could be an indicator that the wine was not kept laid down on its side, so the cork remains wet allowing for a good seal. If the cork dries and shrinks then air and microbes can ruin the wine. If you believe that the wine was not well-cellared then you may find reason to pass on that bottle.           

Wine will penetrate up into the cork as bottles rest in cellar, and this is expected. For some especially old bottles, say 20+ years and beyond, a small amount of wine may actually seep past the cork and begin to degrade the foil capsule. If the wine is indeed ancient you may take this in stride and judge the liquid content on its own merit. If you should see this on a younger wine it could be a sign of a faulty or mal-fitting cork, or that the wine has been subjected to temperature extremes. In this case, beware!

Credit: DrVino.com

What if there is mold on the top of the cork? It is the Sommelier’s task to inspect the condition of the top of the bottle after removing the foil. For older wines it is often necessary to wipe away residue from seepage or foil stuck to the lip. Sometimes there is mold! Not inside the bottle, of course, just where air and spores could get at any tiny bit of moisture and nutrients under the capsule. Completely harmless and easily wiped away before the cork is removed such that none ever touches your wine.

Another rather common reason for mold on the cork is that some wineries, especially in the Old World, will cellar wine in bottles without capsules and labels until they receive an order for shipment. At that time they will label and cap for the specific market where the wine is destined, since many regions have distinct labeling laws (see last week’s “True Facts”). Rustic European cellars are often underground, or in caves hewn into solid rock. These are cool and damp and, yes, very moldy. The mold spores are present on the top of the cork even after the dusty bottles are washed and  the capsules are put in place.  Again, no reason to doubt the wine inside. Just something to take note of.   

Next up: Do you ever find crystals in the bottom of your glass or stuck to the bottle cork?

How about those dark chunks and other “sediment”? And what's the deal with cloudy wine, anyway (a la Seinfeld)?

"True Facts" Read the Label

Deciphering the Wine Label

The Alcohol and Tobacco Tax and Trade Bureau or TTB (how does this acronym fit?) regulates what you see on a wine bottle label. They don’t tell a wine maker if her label art is in good taste (shouldn’t somebody?), but this government body does dictate almost everything else, from font size, warnings about alcohol and pregnancy, to permitted grape varieties and much more. The state of Oregon also regulates some aspects of wine labeling and is actually more restrictive than the Fed.  

The minimum requirements for a US wine label are:

Brand – The big name on the label 

          

Class/Type/Designation – Class separates still wine from sparkling, table from dessert, etc. Designations such as varietal or type and appellation are also important classifications.

Location – Name and address of who and where bottled

Alcohol Content – Wines over 14% alcohol by volume must include this information on the label

Volume/Quantity – Always in metric, may be molded into bottle, but often on the label. See an earlier “True Facts” for all kinds of information on standard wine bottle sizes.

http://www.winepros.org/consumerism/labels.htm

Other label requirements in the US are a Declaration of Sulfites and a Government Health Warning. Why no labeling for the benefits of moderate wine consumption?

Most everything else on the label is optional, but may still come with regulations and restrictions. You can’t say stuff that isn’t true, and for the most part you can’t promise more than you deliver.

http://www.ttb.gov/pdf/brochures/p51901.pdf

You’ll often see vintage on your bottle of Cabernet (or other wine). It doesn’t have to be included, but if it is, in the US, 95% of the wine in the bottle has to have come from grapes harvested and fermented in the specified year. Wine evaporates from barrel and needs to be topped off – often with younger wine. There is that 5% wiggle room to allow this practice. Wines from a single year aren’t necessarily better. Non-Vintage Champagne for instance can be consistent and excellent because it IS a blend of up to several years of wines. On the other hand, when Mother Nature smiles and blesses a certain region with optimal growing and ripening weather, listing that vintage on the label can add cache.    

You may see a viticultural area (AVA) or Appellation listed. This is required if the grape variety is specified on the label, or if vintage is listed or if “Estate Bottled” is mentioned. The Appellation of Origin can be as generic as “American”, state-specific like “California”, or specify a distinct viticultural area such as “Dundee Hills”.

If a specific grape is listed, say Chardonnay, then US law says 75% of the wine must be from Chardonnay grapes.  Only 75%, you say? Well the state of Oregon says 90%!  http://arcweb.sos.state.or.us/rules/OARS_800/OAR_845/845_010.html

What about those big jugs on the bottom shelf of the supermarket labeled with terms such as Chablis, Madeira, Burgundy, Sherry, etc., or that low-dollar Champagne from California? Weren’t those producers supposed to stop co-opting the famous place and origin names?  Well, any label approved prior to March 10, 2006 is “grandfathered” in, but for all production since and moving forward the US has reached an agreement with European Community to restrict this once popular generic use of the famed names. http://www.ttb.gov/agreements/us_ec_wine_agreement.shtml

Some terms such as “Reserve”, “Old Vine” and “Chateau” are essentially unregulated in the US (but strictly regulated in other countries) and can be used or misused by anyone – buyer beware!

Other terms you might see on front or especially back labels might be:

Neutral Oak – For most winemakers this means use of oak barrels older than 3 years. After repeated use most of the effects on wine of oak from a barrel become imperceptible. By putting this on his label the winemaker wants you to know that you will get more pure fruit aromas rather than the buttery tones from newer wood.   

Stainless Steel-aged is related to this in that stainless steel is very neutral and non-reactive, adding nothing to the wine nor taking any character away. You’ll often see this mentioned on bottles of aromatic and fruity whites.

Residual Sugar (or RS) - another term that is not required and has to be true if mentioned. It is also a term that can be very useful information for the consumer. The term refers to sugars left over in the wine when fermentation is stopped (hence residual). This is measured and indicated by grams per liter or g/L. Over 2 g/L residual sugar is when a wine can become perceptibly sweet, and below that is an essentially “dry” wine. Dessert wines can be in the 30 to 150 (and more) g/L range of residual sugar. Lots of factors determine how sweet a wine seems apart from the actual level of RS, however. Use the label information as a general guide to a wine’s sweetness.

  

Barrel fermented vs. Barrel Aged – in short, “barrel fermented” doesn’t tell you if a wine will have characteristics of an oak barrel. Winemakers choose to ferment white wine in particular in barrel for a creamy, round character. Barrel-aged is just as it sounds – storing the wine (particularly reds) in wood for tannin integration, and oaky, toasty, spicy flavors.

Sur Lie – is a label term somewhat related to barrel aging in that the wine had been left to rest on the spent yeast cells which are even sometimes stirred up (bâtonnage in French) to slowly resettle at the bottom of the barrel.  Sur lie aging can give added character to a wine in the form of yeasty (obviously), biscuit or bready notes.

Organic – Seen more and more on wine labels. I’ve covered this in prior “True Facts” and will again, for sure. Organic can refer to the grapes having been from a certified organic vineyard. The wines from these “hippy” grapes may or may not be made to organic standards (very regulated and specific, BTW). Wines made to organic standards will not have added sulfites and may be label as such.

"True Facts" Malo what?

Right about now in the local wineries the fermentation process is over and many of the new wines are resting in barrels, tanks or bottles. But wait, that’s not all… as far as fermentation goes.

We all know that wild or commercial yeasts are put to work on the freshly picked grapes almost as soon as they come in from the vineyard. This is the primary fermentation stage where the grape sugars are consumed by the yeasts and converted into alcohol (and carbon dioxide); where grape juice becomes wine, essentially.

What happens next, for most red wines, as well as for selected white wines like Chardonnay, is that ANOTHER fermentation stage is initiated. And confusingly/maddeningly this stage is technically not about fermentation really, but about acid conversion.

 

What is often referred to as secondary fermentation process is called malolactic fermentation, with winemakers shortening the term to “ MLF” and tasting room hosts tossing it off as “Malo”.  In short, what happens in the wine is that the hard, green apple-like and tart malic acid is converted into softer, creamy, even butter-like lactic acid.

Malic acid is the primary acid component of apples (mālum in Latin = apple) giving them their delicious tartness. Lactic acid is the main acid in fermented dairy products like yogurt, (in Latin lac, lact- = milk) and it is much less tart in comparison.

You don’t want your Pinots or Cabernets to taste of green apple, but you just might like your Chardonnays to be creamy and buttery, so it is up to the winemaker to get this malolactic conversion going. Bacteria does the work here rather than yeast, specifically Oenococcus oeni (formerly Leuconostoc) bacteria (sometimes lactobacillus and Pediococcus). The bacteria, like yeasts, can be naturally occurring, but since the MLF process can be difficult to control, and in some cases difficult to start, winemakers often inoculate with commercially-prepared cultures. The MLF can still be a winemaker's headache and depending  on weather and cellar conditions, for example, it may not even be completed until spring!

  

In general, wines that are prevented from going through malolactic conversion have a high concentration of malic acid and therefore a perception of vibrant crispness and fresh fruit. Riesling is a wine that seldom is (and probably should NEVER be) allowed to undergo malolactic conversion. Riesling's high natural acidity is one of its desirable traits and core structure.

Wines that have gone through partial or complete malolactic conversion have a decreased perception of acidity, and have traded fruit and varietal aromas for fuller mouthfeel and a buttery flavor. A winemaker may choose only allow some of his, say, Chardonnay juice to go through MLF while leaving some juice with higher malic acid to add a vibrancy and balance to what otherwise might be a flabby and creamy wine. Some people like it that way. Who am I to judge? 

One more reason that many wines are allowed or made to undergo MLF is that you don't want this process to happen spontaneously in the bottle! A by-product of MLF is CO2 which would give the wine an unexpected (and unwanted) spritz and could push out the cork or burst the bottle.

So we know that Malic acid is exactly one of the components making an apple taste apple-y, but it is also interesting to learn that a by-product of the malolactic conversion called diacetyl, is exactly what makes foods from movie popcorn to margarine to actual butter taste buttery!

<Geek Alert>

Recent research hints that the conversion to lactic acid may release more than just a buttery character, but may also free up bound aroma compounds that are stuck to sugar molecules. Wine Aromas and MLF 

Otherwise trapped or glycosylated aroma compounds are released during malolactic fermentation which suggests that O. oeni can alter the sensory characteristics of wine through the hydrolysis of aroma precursors.

</Geek Alert>

Wow, the bound up aromas can't be smelled, but MLF bacteria work overtime to free them so they can waft to your nose.