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Bottle it up!

June 10, 2021

There is nothing more satisfying than a rollicking good debate, in my opinion. Preferably fact based, and on a topic I’m hungering to know more about.

And since we are up to our earballs in “debate land” territory, and our country seems more divisive than ever, I figure we should take advantage of the heightened state of information gathering our brains are working to maintain and toss yet another subject of controversy at it.

Whiskey closures.

Recently, we’ve had a couple of questions from Facebook and Instagram on the subject, and you might be surprised to discover that the “best sealing practices” debate is more complex than one would think.

It’s true, this may not be an issue keeping many of you up at night, but it’s a genuine concern within the wine and spirits industry.

The choices used most widely now are:

  1. Natural Cork
  2. Synthetic Cork
  3. Screw Caps


Ultimately, the right “fit” comes down to science, cost, sustainability, and sensibility.

We know that both industries must consider OTRs—oxygen transmission rates.

For cellar-worthy wines, the slow interaction with air is beneficial, so using natural cork, which can allow volatile gasses to pass through the plant-based material, will help with the desirable aging process. Wines meant to be enjoyed young, fresh, and immediately are often capped with a screw top closure, as it’s a secure sealant and is less expensive than cork.

Whiskey, on the other hand, has a different outlook.

Barrels are for maturation, bottles are for preservation.

Choosing natural cork to seal a bottle of whiskey has both benefits and risks.

  1. Cork is expensive—if chosen, it may add a few precious pennies to the overall cost.
  2. There exists a firm debate over whether the cork bark harvesting industry is as carefully regulated as it once was. We add to this list the effects of climate change, making quality a growing concern.
  3. TCA—2,4,6-Trichloroanisole—is a chemical compound found in contaminated wood products responsible for “cork taint” in wines and spirits. If discovered to have infected the product, it creates a musty, wet cardboard type of aroma and flavor.
  4. Natural cork, when used for high-proof spirits, can disintegrate, crumble, and lose its sealing power.
  5. Natural cork is recyclable.
  6. Natural cork is visually appealing and contributes an authentic historical feel to the bottle which can enhance the perceived quality of the wine or whiskey.


The decision to use synthetic cork has pros and cons as well.

  1. It’s said to provide a tighter seal, thereby ensuring less evaporation and less chemical interaction with any volatile gasses permeating through the closure.
  2. Synthetic cork—although not typically biodegradable—may be recycled if they are manufactured from plant-based materials (but even many of the plastic-based corks are recycled into shoes, bags, and flooring.)
  3. They do not break, disintegrate, mold, or crumble.
  4. Studies are ongoing as to whether polyethylene—the plastic-based cork—can deliver off notes to wine or spirits, although the companies that manufacture these corks state there is no data to show this as true.
  5. Studies are ongoing as to whether polyethylene—the plastic-based cork—can deliver off notes to wine or spirits, although the companies that manufacture these corks state there is no data to show this as true.
  6. Synthetic cork is less expensive.


And lastly, screw caps.

Growing in popularity, they share many of the same clear benefits as synthetic cork but suffer from a larger carbon footprint than their counterparts, despite the rosy glow of their aluminum recyclability.

There are copious examples of highly respected whiskies that use screw caps (Nikka, Suntory, Old Weller Antique, and Old Granddad), those that use synthetic (Defiant, Joseph Magnus, Baker’s Single Barrel, and Reservoir!), and plenty that stick with natural cork (a great number of single malt Scotch whiskies—Glenfiddich, Glenmorangie, and Laphroaig).

Our goal here at Reservoir is to provide you with an unparalleled experience from grain to glass, product to packaging. Our choice to use synthetic cork has been one carefully reviewed for 11 years running.

But despite our best efforts, once you bring our spirits home, storage is something worth a moment of thought. We offer you a few sage tips to keep your whiskies in their best condition:

  • Store your bottles upright—especially if they have natural cork as their enclosure.
  • Keep your spirits out of direct sunlight, and preferably in a dark, cool area.
  • Once there is more space than spirit in the bottle, consider transferring the whiskey to a smaller glass bottle, or fill the original bottle with marbles, or utilize preserving sprays. We suggest having a few friends over and finishing those last lovely drops.

So, there we have it, ladies and gents. I hope I’ve been able to highlight many of the myriad elements we take into consideration when making the choice on this consequential decision.

It may not be as monumental as the outcomes on healthcare, but we take great pains to create a whiskey we think you’re going to love and one that’s going to last.

You can even call your high-quality whiskey needs medicinal.

We promise not to argue on that one.

~Shelley Sackier—Director of Distillery Education