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You’re out at a nice restaurant and decide to treat you and your guests to a bottle of wine. After placing the order, the sommelier shows you the label, opens the wine, and pours a tiny bit into your glass to taste before serving to everyone else. But why? Despite many people assuming this is to ensure the guest actually likes the taste of the wine, it’s actually not about that at all. It’s an antiquated practice of allowing the guest to test if the wine is spoiled, or “corked,” as they refer to it in wine speak. Although it’s generally rare to be served corked wine, don’t feel embarrassed if you don’t know the identifiers of a wine gone bad. It’s not just you. Most guests don’t actually know what they’re looking for in the first place. 

So let’s talk about it! There’s more nuance here, but to simplify it a bit, there are two main ways a wine can go bad. A) It’s “corked”. A corked wine has been exposed to unwanted oxygen and a chemical compound TCA (more below) while in storage and emits aromas of wet cardboard or moldy floor. B) It’s “cooked”. A cooked wine has been subjected to hot weather, too much sunlight, or multiple, significant temperature fluctuations. This wine is going to lose complexity. It could smell like overly jammy fruits and when you drink it, it could lose its tannin structure and can taste watered down, or more like grape juice mixed with alcohol. If you’ve ever left a red wine open for too long and tried to drink it, it’s a similar off-putting taste to that, but sometimes it’s hard to tell if a wine is cooked, especially if you’ve never had that specific wine before!

How does a wine become corked in the first place? Corked wines are the byproduct of unwanted fungi that permeates the cork itself forming a chemical compound called TCA. Two common reasons this could happen are: a) the corks were exposed to this fungi or tainted at the winery itself when bottled or b) the bottles may have been stored upright for too long (e.g., not touching liquid) reducing the cork’s size and allowing too much oxygen into the bottle. Technically this premature oxidation is a slightly different chemical reaction but often referred to as “corked” wine anyway. Historically corked wines were more prevalent than they are nowadays due to more sophisticated transportation and storage, the use of screwtops, and better winery/production hygiene.

As for cooked wine, this tends to be the more common culprit of spoiled wine, but may often be referred to as “corked” anyway. “Corked” is often used as a catch-all term for, “there’s a flaw in this wine.” Even if wine is stored improperly for just a few hours (as little as 3 or 4 in some cases), weather, temperature, and sunlight can have a dramatic impact in a short amount of time. Too much sunlight causes UV rays to create unwanted sulfur compounds in the wine (rotten egg or skunky smelling). Exposing the wine to temperatures above 90 degrees or too many temperature fluctuations of 20 degrees or more will prematurely and rapidly age the wine in unwanted ways inside the bottle. I see this happen way too often when friends visit multiple wineries in Napa over the summer. They’ll buy a bottle or two from the first winery of the day, leave them in their car trunk exposed to 90-100 degree temperatures for several hours during winery two and three, and by the time they’re done with tastings, the wines from the first location are beyond saving. Pro tip: To be safe, take your bottles with you into each subsequent winery, and ask the employees to store it for you while you taste. It’s worth it!

At-home storage is another common culprit leading to cooked wines. Let me tell you about my own unfortunate experience…Up until a couple years ago, I only had a small wine fridge, but the problem was that at any given time, I had about 50 bottles to store. In a tiny 1-bedroom, 700 square foot apartment on the 10th floor of a building, that doesn’t leave you with many options. Being cognizant of sunlight exposure, I used the only place in my apartment that was always dark, under my bed frame. This worked well for years because in San Francisco, the temperature in my apartment never dramatically changed. However, the summer heat wave in 2019 did me in. After just one month of temperatures nearing 100 degrees F outside, I hadn’t realized it, but my apartment was consistently shifting from ~85 degrees during the day to ~65 degrees at night. Once temperatures dropped again in late summer, my “under the bed” wines had experienced consistent and extreme temperature fluctuations of 20 degrees multiple times. 

As I tried one of my favorite bottles, I began to suspect the worst. The wine smelled a bit like the jam in my fridge and lacked many of the other complex smells I remembered were in it. But I held onto hope! I timidly took a sip and was quickly disappointed by tasting watered down wine, like grape juice with too much alcohol burn, and none of that dryness in the mouth that typically rounds out a great cab’s texture. It tasted more like boxed wine from a frat party. Over the course of the next week I tried each and every one of those “under the bed” wines. Needless to say, most did not survive the first sip…I learned a valuable and expensive lesson about wine storage that week and promptly upgraded my wine fridge to avoid any future heart wrenching spoilage. 

Under the bed storage, works it does not”


So, what are your options if you don’t have a wine fridge or capacity left? A dark room/cabinet option could work as long as you have a method of constantly temperature controlling (and you definitely don’t want the wine to be too close to a washer/dryer or any type of heat source). Remember, the easiest wine spoilers will be extreme temperatures and rapid fluctuations in temperature. With that in mind, here are some other tips to avoid spoiling your precious wine collection (cue my PTSD)!

  • Affordable wine fridges for <$200 on Amazon like this and this
  • Non-fridge alternatives to minimize sunlight exposure: Underground parking garage, basement storage unit, closet (if A/C is available)
  • Extending an open wine’s life: Vacu Vin (~1-2 days for red, ~2-3 for white)
  • Trying a “splurge wine” without having to finish it: Coravin


I’ll leave you with a few other things to watch out for related to spoiled wine: 1) Beware of fluorescent lights like the kind you might find within your actual fridge or illuminating your kitchen. These emit the same UV rays that the sun does, so prolonged exposure (3 hours for clear bottles and ~20 hours for green bottles) will cause similar damage. 2) Be selective when buying pricey or especially “splurge” wine. If you’re going to buy a bottle that’s >$50 I’d highly recommend going to your local craft wine merchant. I’ve seen way too many instances of corner liquor stores or even Bevmo (gasp!) where wine is stored in a subpar fashion (too much light exposure, not temperature controlled, bottles standing up for extended periods) .

Just like proper food storage, wine storage is very important to quality control and protect your wines. Although most “bad” wines won’t necessarily hurt you if you drink them, it’s obviously a subpar experience. If you’re going to invest in a nice bottle of wine and/or try to age something make sure you have an appropriate storage set up to do so to get the best out of each bottle. Cheers!