Unfortunately, you kind of need to understand other sparkling wine production in order to understand Pet-Nat aka "pétillant naturel” aka “methode ancestral.” "Pétillant naturel” loosely translates to "naturally sparkling" in French. Where does the term "methode ancestral" come from? Pet-nat is debatably the oldest method of creating sparkling wine that we know of. It's an old, pure, raw, rugged way of producing sparkling wine. We'll talk about the Champagne Method, then the Charmat/Tank method, which is most famously used in Prosecco and Lambrusco production, and lastly we'll chat pet-nat.
First let's talk about Méthode Champenoise aka The Traditional Method aka The Champagne Method
The Champagne Method is the technique they use in... you guessed it! Champagne, France. The Champagne Method aka the Traditional Method is a long complicated process that they make you memorize for wine exams. But here's the gist:
- Make dry still wine
- Add sweet liqueur and yeast to the wine and bottle it. Then seal it with a beer/crown cap
- Secondary fermentation takes place in the bottle because there is sugar (liqueur) for the yeast cells to eat. This second ferm leaves the wine without any sugar left, and is what creates the bubbles.
- DISGORGEMENT: This is a labor intensive process that involves collecting the lees (aka dead yeast cells aka sediment) in the bottleneck, freezing said bottleneck/lees (not the whole bottle) in a cold brine, and finally popping the crown cap to violently expel the lees from the bottle.
- Dosage: Add (or don't add) Liqueur d'expedition to achieve the producers' desired sugar/dryness level.
- Cork it, wire it shut, label it.
- So the main takeaway is: With the Champagne/Traditional Method, the second fermentation takes place INSIDE the bottle- this is what creates the carbonation.
This is how Prosecco and Lambrusco are made. The Tank Method is much easier, less labor intensive process that is good for two things:
- Mass production
- Preserving varietal characteristics and purity of grape expression. So it's good for extroverted/aromatic/fruity grape varieties like Glera (Prosecco) and Lambrusco.
- Instead of the secondary fermentation happening in bottle, it happens, you guessed it, in a large tank
- The base wine and the sugar/yeast mixture are dumped into the tank.
- The secondary ferm takes place in the tank and thus magical bubbles are created.
- The lees and sediment are filtered.
- The expedition liqueur is added (or not added) to the tank to achieve the sweetness/dryness level the producer wants.
- The sparkling wine is bottled/corked/wired/labeled.
- Essentially the Tank Method is done in a large tank because it's easier and cheaper than carrying out the process in a million individual bottles. Typically it's used for mass production commodity rather than for artisanal labors of love.
Pet-Nat aka "pétillant naturel” aka “methode ancestral.”
So pet-nat is more similar to the Champagne Method than it is to the Tank Method. Why? Because the SECOND FERMENTATION HAPPENS INSIDE THE BOTTLE IT IS SOLD IN. Here we go again. Am I experiencing déjà vu?
- Make still wine, except this time, at the perfectly opportune moment during fermentation...
- We're going to bottle the wine mid-fermentation while there's still some residual sugar (RS).
- Close it with a crown/beer cap, trapping the CO2
- Because there's RS and yeast left in the wine, a secondary fermentation occurs IN BOTTLE (Remember? Yeast eats sugar until there's none left)
- The end. That's it. There's no disgorgment. No filtration process. That's why there's sediment in Pet-Nat.
The main thing to know about the secondary fermentation happening in bottle is that it gives the final wine a "leesy" aka "leesy cheesy" smell.
Have you ever noticed how Champagne and Pet-Nat can have aromas reminiscent of dough, bread, beer, freshly baked pastries, brioche, buttered toast, etc? That's all because of the lees. And once you train your nose to smell these aromas, you'll weirdly get obsessed with them?
Champagne vs Pet-Nat
Champagne leans toward being more refined, elegant, focused. More of a Johhny-High-School, starting Quarterback, prom king/queen type. Whereas Pet-Nat is more raw, rustic, rough around the edges. More of an unpredictable, denim-jacket-wearing, marlboro-red-smoking, regular detention type. Both are delicious! Pet-Nat tends to be more affordable since it's less labor-intensive to make and has not been marketed as a luxury product.