Malolactic Fermentation

This week’s Wine-Ucation will be a short one but for all you wine tasters out there who’ve been to a tasting table and heard the pourer talk about Malolactic Fermentation and nodded in agreement to a term unbeknownst, this one’s for you.

So, what the heck is Malolactic Fermentation (we’ll call it ML like the cool people do)?  Let me start by saying first and foremost, it’s not really fermentation in the sense we most often think of the term…using yeast to convert fermentable sugars into ethyl alcohol.  By the book, fermentation, in general, is the metabolic process of breaking down a substance through yeast, bacteria, or other microorganisms producing alcohols, acids, and gas.  Unlike the use of yeast in the creation of the alcohol in wine we all adore; ML utilizes bacteria.

Enter Oenoccocus Oeni…which from here on out, we’ll refer to as Double-O.  Double-O is a bacterium that when introduced to wine, results in ML.  It’s quite simple honestly…the Double-O consumes the Malic Acid and converts it into Lactic Acid.  Why?  What’s the difference?  

Well, Malic Acid is what people are referring to when they speak about the acidity of a wine…it’s tartness.  Have you heard a pourer say something like, “…balanced by a nice acidity…”?  I have many times.  On the other hand, Lactic Acid is far milder to the pallet.  You’ll often hear that it softens the wine…makes it creamier.  Some even say it gives the wine a little oiliness.

Now comes the question…which wines allow ML to take place?  A general, but not always 100% accurate, way in answering this is anything aged in oak as Double-O is naturally occurring and native to it.  Don’t get me wrong…you can add Double-O to wine being aged in steel and even wines that are to be aged in oak as to give it a boost to get the process going.  So, I would argue nearly all red wines have gone through malolactic fermentation to some extent. In white wine, it gets a little more complicated.  

Some whites are aged purely in Stainless Steel and are most often those crisp, tart, and acidic wines we love in the summer.  Sauvignon Blanc is a perfect example.  Other whites are thicker, creamier, and softer.  Think a buttery Chardonnay or here in Virginia, Viognier.  These wines have a bigger body to them.  The flavor coats your mouth.  

From my experience, it’s a love or hate relationship as your typical ABC’er (Anything But Chardonnay) isn’t normally someone against the Chardonnay Grape itself, but the amount of ML it’s gone through.  The interesting thing is, there’s often a middle-ground to whites.  Pourers will often say partially aged in oak and that means simply that some of the wine was aged in stainless steel and a certain portion in oak in order to get somebody and softness from ML.  

Winemakers also need to be careful in that too much ML doesn’t take place in certain styles as it can rob the floral and citrusy flavors prominent in certain styles and loved by so many drinkers.

So…hopefully this clarifies ML and now when you have someone pour you a glass of Viognier or Chardonnay at your favorite winery and throw in the term, you can nod your head in agreement/knowledge rather than embarrassment/confusion.