How Long Does a Keg Last? A Complete Guide

by Dane Wilson | Last Updated: May 14, 2025

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You’ve invested in your kegerator setup and bought quality beer, but you’re still not sure if that keg is past its prime or how long it’ll last. The uncertainty leaves you second-guessing every pour and potentially wasting money on beer that’s lost its magic. Understanding how long does a keg last depends on beer style, storage conditions, and dispensing methods. IPAs stay fresh for 45-60 days, while stouts can last up to a year. Temperature control, CO₂ systems, and pasteurization all impact freshness. Learn the critical storage factors that make or break your beer’s lifespan and the telltale signs that separate great beer from garbage.

Table of Contents

• Types of Kegs
• Keg Freshness by Beer Type
• Factors That Affect Keg Life
• Pasteurized vs Unpasteurized Beer
• Kegerator Use
• Hand Pump vs CO₂ Tap
• Signs of Spoiled Beer
• Keep Your Keg Fresh
• FAQs

Types of Kegs

Understanding keg varieties is essential for getting the best experience from your draft beer system. Different sizes and styles serve specific purposes depending on your volume needs and brewing setup.

• Cornelius Kegs: Called “Corny kegs,” these hold 5 gallons and were originally designed for soda companies like Pepsi and Coca-Cola. They feature a large removable lid that makes cleaning and filling easy, plus two posts on top for connecting gas and liquid lines separately. Available in ball-lock (more common and taller) and pin-lock (shorter and wider) versions, each using different securing systems to prevent connection mix-ups. They allow you to carbonate and dispense from the same container, giving homebrewers complete control over the carbonation process.
• Pony Kegs: Also called quarter barrels, these hold 7.75 gallons and serve about 62 pints or 82 bottles worth of beer. Available in stubby (short and wide) or slim (tall and narrow) versions, with the slim fitting better in dual-tap kegerators.
• Half Barrel Kegs: These hold 15.5 gallons and serve approximately 165 bottles or 124 pints. Standard for high-volume bars and restaurants, they use Sankey valve systems requiring couplers for dispensing.
• Commercial vs. Home Use: Commercial kegs use Sankey couplers with single-port systems, while homebrew kegs feature separate gas and liquid connections. Commercial kegs aren’t designed for easy opening, cleaning, and refilling, making them unsuitable for homebrewers who need to reuse their containers.

Keg Freshness by Beer Type

Not all beers age gracefully in kegs – it’s like comparing a delicate rose to a sturdy oak tree. The style of beer you’re storing plays a massive role in how long it’ll maintain that fresh-from-the-brewery taste.

IPAs are the prima donnas of the beer world. IPAs are typically unpasteurized, which gives them a shorter shelf life of around 45-60 days when stored properly. Those beautiful hop oils that create citrusy, piney flavors start breaking down almost immediately. While the bitterness profile will last for a long time, the aroma will start falling off immediately, but becomes perceivable after 2-3 weeks. That gorgeous hop aroma hitting your nose? It’s the first casualty in the battle against time.

Lagers are the marathon runners of beer storage. Lagers generally last 6-12 months unopened, and they maintain their character remarkably well in kegs, too. Their simple malt profile means there’s less volatile stuff to degrade.

Here’s the surprise winner: stouts and porters are longevity champions. Stouts and porters can last up to 1 year unopened. Those roasted malts contain natural antioxidants that fight off oxidation, making your porter a reliable long-term kegerator companion. Some improve with age, developing smoother, more complex flavors over months rather than deteriorating.

Related: The Ultimate Guide to Keg Sizes

Factors That Affect Keg Life

Temperature Control: This sits at the top of the throne when it comes to keg longevity. Temperature significantly influences the beer’s quality, with optimal storage typically between 38-42 degrees Fahrenheit. Here’s the kicker – consistency matters more than you might think. Constant temperature fluctuations, like moving a keg in and out of cold storage, can ruin beer’s freshness. Temperatures above 55 degrees Fahrenheit will likely cause your beer to grow bacteria and increase your chances of premature spoilage.

Oxygen Exposure: Beer’s absolute arch-nemesis. Once wort has fermented into beer, it’s vital to keep it as oxygen-free as possible. When oxygen sneaks into the party, it creates those dreaded cardboard-like flavors. Your CO₂ tank becomes your best friend here, creating a protective blanket that keeps the bad stuff out.

Other Critical Factors:

• Carbonation levels – Aim for 2.2-2.7 volumes of CO2 for most styles to maintain both flavor and longevity
• Light exposure – Exposure to light, especially sunlight, causes a chemical reaction in the hops that gives beer that infamous “skunky” flavor.
• Handling – Rough treatment disturbs the sediment and creates foam issues
• Line cleanliness – Poor maintenance introduces bacteria that’ll ruin your beer

Pasteurized vs Unpasteurized Beer

Think of pasteurization as your beer’s insurance policy. Pasteurized beers generally maintain their freshness longer, with an average lifespan of about 90 to 120 days, while unpasteurized draft beer can expect a freshness period of around 45 to 60 days. That’s double the shelf life from a quick heat treatment that kills troublesome bacteria.

Large breweries pasteurize their beer, whereas many small craft breweries do not. The equipment to pasteurize is expensive, and many microbreweries cannot afford the investment. Craft breweries design their beers to be consumed in the tap room or in a short window of time at a location close to the brewery. When kegs move fast locally, that shorter unpasteurized shelf life works fine.

Kegerator Use

Your kegerator creates the perfect environment for maximum keg longevity. If refrigerated within a kegerator that uses CO2, a keg will generally last at least 6-8 weeks before it starts to lose its fresh taste. That’s your baseline expectation when everything’s dialed in correctly.

Ideally, both the beer keg and the CO2 tank should be stored inside your kegerator fridge: the lower the temperature of your compressed air tank, the more efficiently it will carbonate your beer. Your pressure regulator becomes crucial here. Most American breweries recommend a pressure between 10-14 PSI. This maintains that a protective CO₂ blanket keeps your beer fresh for weeks.

The CO₂ system makes all the difference compared to party pumps that give you maybe 12-24 hours. Your kegerator’s setup extends that timeline to 6-8 weeks of consistent quality. If you store it at the appropriate temperatures, pasteurized beer will last you at least three months, sometimes as long as six months. Unpasteurized beer will only last two months.

Hand Pump vs CO₂ Tap

The dispensing method you choose becomes the ultimate game-changer for your keg’s lifespan – it’s the difference between a sprint and a marathon. Using a picnic pump, party pump, or keg tap is a completely different situation. These introduce oxygen into your keg, which greatly speeds up the process of beer going bad. Since a picnic pump uses oxygen instead of carbon dioxide, a tapped keg will only last about 12-24 hours.

If you introduce air into the beer, it will go bad in about a day or two. Oxygen, which is in the air, oxidizes the beer, which gives it a nice wet cardboard taste. That hand pump might look budget-friendly, but it’s essentially giving your beer a death sentence.

CO₂ systems flip this script entirely. For longer events or commercial settings, a CO2-based keg tap system is preferred. It maintains the keg’s internal pressure and prevents early spoilage, keeping the beer fresh for weeks. It takes one cartridge to dispense a 1/4 keg and two for a 1/2 barrel.

Related: An Introduction to Home Kegging

Signs of Spoiled Beer

Smell indicators:

• Sour, vinegar-like aromas from oxidation
• Cardboard or musty scents from staleness
• Skunky smell from light exposure
• Rotten odors from bacterial infections

Visual clues:

• Cloudiness or sediment in normally clear styles
• No beer foam when pouring (indicates flatness)
• Film-like sheen on top resembling thin white ice sheets (infection from wild yeast like Brettanomyces or lactobacillus)
• Unusual color changes

Taste problems:

• Skunky flavors from light damage
• Stale “wet cardboard” taste from oxidation
• Vinegary flavors from acetic acid in dirty lines
• Buttery taste from diacetyl contamination
• Rancid, cheesy, or spoiled milk flavors from lactic acid produced by bacterial infections

Keep Your Keg Fresh

Your keg’s lifespan isn’t left to chance – it’s completely within your control when you understand the fundamentals. Temperature consistency between 38-42°F serves as your foundation, while CO₂ systems extend freshness from mere hours to 6-8 weeks compared to hand pumps.

Beer style makes all the difference: IPAs give you 45-60 days of peak flavor, lagers stretch to 6-12 months, and stouts age gracefully for up to a year. Pasteurization doubles your timeline, providing 90-120 days versus 45-60 days for unpasteurized craft beer. Master these fundamentals, and every sip tastes exactly as the brewer intended.

FAQs