Traditional Cork vs Screw Caps???
I'm part of a few "foodie" & wine Facebook groups. Last week, a member of one of these groups asked why some wineries use traditional cork and others use screw caps as their means of closure. I was then asked again this past Sunday at the French wine tasting I've been running this month. So with all the interest....let me shed some light on this topic and at the end, you can decide which one is better given the facts....
Up first, we have the traditional, old-school, OG's of the wine world; cork closures. We can find evidence of corks being used back to the ancient Greeks and Romans. The cork is one of the few natural options that is malleable enough to seal the bottle. However, you can't just take the bark from any tree you find in your backyard. These corks come from the bark of Quercus suber, conveniently known as the cork oak tree. Okay, okay okay...enough of the history lesson, what's the hype here? Here are the Pros and Cons:
Tradition. There is something nostalgic & romantic about popping out a wine cork. It has been historically preferred and I don't see it being phased out anytime soon.
Renewable Resource (sort of). Because corks are derived from the bark of a cork oak tree, it is renewable. Most of these trees are located in parts of Portugal & Spain. Due to increased demand of wine and therefore cork, these parcels of forests are strictly protected to supply the world demand. However, each tree can only be harvested on average once every decade making it an extremely slow process of "renewable."
Cellar Worthiness (Proven). Due to cork's long track record as a closure for wine, we have been able to prove the effectiveness of corks when it comes to the aging of a bottle of wine. At a detailed level, the tiny pores of the cork allows minuscule amounts of air to enter the bottle while keeping the liquid inside from escaping. The interaction of minute oxygen with the wine helps transform the wine over time.
Susceptible to Taint. Taint refers to Trichloranisole (TCA). A chemical compound that can affect wood-derived materials. It isn't harmful to humans but can adversely affect the wine. It causes the wine to smell like wet cardboard or wet dog. Trust me...it isn't pleasant and it can be disappointing to open a highly anticipated bottle of wine to find out it is "corked." Recently, there's been advances in methods of removing/preventing TCA from corks. While promising, the science is still isn't 100%.
**Side Note** If you do open a bottle of wine to find it "corked," don't throw it away! You have two options:
1) Most of the time, you can bring it back to the wine shop. Any reputable wine shop will exchange it out for another bottle. They will take the "corked" bottle and return it to their distributor.
2) You can still use it to cook with. I wouldn't do it in a stew but if you need wine as an ingredient for a sauce, the TCA will cook off and the wine will still help enhance the recipe!
Variability in Quality. Cork is a natural product, each one is slightly different. Winemakers and vineyards try their best to keep consistent but there is always a slight difference in corks. Without getting too in the weeds, each cork varies in porousness therefore, interactions with oxygen can be slightly different .
Cost. I'll keep it simple. Corks cost up to 3x more than screw caps. That cost certainly contributes to the overall cost of the bottle.
The challenger is the new(ish) invention and usage of screw caps. Screw caps came to be popular out of necessity. Low quality cork manufacturing in the 1970s & 1980s forced winemakers to find alternative solutions. Pioneered by winemakers in Australia, screw caps have become increasingly popular. Why you ask? Well, let's take a look:
Affordable. Screw caps are made from common metal and plastic. It is certainly the cheaper option when compared to corks.
No "Cork" Taint. There is no TCA taint because metals & plastic can't be affected by the chemical compound. So in terms of consistency, screw caps get a big win. To be transparent on one note though, the oak barrels that winemakers use can still be tainted..so it's not a guarantee that the wine will never be flawed.
Cellar Worthiness (subjective at best). Because screw caps keep oxygen out, they're believed to be longer lived. Proponents of screw caps cite that with limited or no oxygen contact, the wines don't age at all! But it is controversial...some argue that the small amounts of oxygen corks allow create a better, aged wine.
User-Friendly: No one is judging you...so let's be honest. Do you remember the first time you tried to use an old-fashioned wine opener? Didn't go very smoothly huh? So big plus here is you can access the yummy wine with a simple twist of cap.
Mostly made from Non-Renewable Resources. If you love the environment, screw caps are not your best friend. Most screw caps are made from aluminum and the liners are made from Polyvinylidene Chloride (PVDC). So to break it down (pun intended), Aluminum is not biodegradable and recycling it negatively impacts the environment. PVDC is considered toxic when burned and has actually been placed on a number of banned lists in Western Europe.
Variable Manufacturing Quality. Just like any other manufactured good, the quality of screw caps are subjected to how well it is manufactured. Poorly made caps can break or bend too easily.
Associated with Cheap Wine. There are world class wines that use screw caps but often, screw caps are associated with cheap wines. Some theorize because it got its fame in newer winemaking countries (i.e. Australia) that don't have the lineage, fame, and history of older winemaking countries like France, Spain, etc.
Prone to Reduction. First, reduction is caused by minimal oxygen contact. Sulfur Dioxide can't escape or can't be absorbed into the wine. This causes smells like rotten eggs to be present in the wine. No bueno.