Beer Beyond Best Before: Is It Still Good?

Beer is produced with expiry dates, but these are more of a guideline on quality than safety. While the taste and fizz of the beer may deteriorate over time, it is unlikely to make you sick. This is because the alcohol content and the presence of hops, which have antimicrobial characteristics, prevent pathogenic growth. However, the shelf life of beer depends on various factors, such as the type of beer, the colour of the bottle, and storage methods.

Beer Past Its Best Buy Date

Beer's alcohol content and hops prevent bacterial growth

Beer is a drink with a long history, and its consumption dates back to ancient times. Over the years, beer has been recognised as a drink that is resistant to the growth and survival of microorganisms. This is due to a combination of factors, including the presence of ethanol, low pH, high carbon dioxide concentrations, and low oxygen content. Beer also contains hops, which have antimicrobial properties and play a crucial role in preventing bacterial growth.

The antimicrobial effects of hops have been recognised for centuries, with records dating back to the 12th century. The addition of hops helps to "'keep away certain putrefactions from beverages," as noted by Hildegard von Bingen in the book "Physica". Modern scientific research has confirmed the antimicrobial properties of hops, particularly against gram-positive bacteria.

Hops contain alpha acids, which contribute to the bitter taste of beer and also possess antimicrobial properties. Beers with higher bitter units (BU) tend to have higher concentrations of alpha acids, and these acids provide protection against bacterial growth during the early stages of fermentation. Late hop additions in the brewing process can result in higher amounts of alpha acids in the cold wort, enhancing the antimicrobial protection.

While hops play a significant role in preventing bacterial growth, other factors also contribute to the stability of beer. The fermentation process itself creates an environment that inhibits bacterial growth. As yeast ferments sugars into ethanol, the pH decreases, carbon dioxide is produced, and the alcohol content increases, creating unfavourable conditions for bacteria.

Additionally, the type of beer also affects its susceptibility to bacterial growth. Wheat beers, low alcohol beers, and alcohol-free beers are more sensitive to bacterial contamination. On the other hand, beers with higher alcohol content, such as porters and stouts, can improve with age, similar to wine and whiskey.

Overall, the alcohol content and hops in beer work together to prevent bacterial growth. The antimicrobial properties of hops, combined with the unfavourable conditions created by the fermentation process, make it challenging for bacteria to survive and grow in beer.

Beer's flavour and aroma change over time

Beer flavour stability is of considerable importance in today's demanding beer market and has become one of the highest technical challenges facing brewers. The flavour changes that occur over time are almost always unpleasant and unintended. The flavour stability of beer is influenced by several factors, some of which are disputed, but oxidation plays a crucial role.

Oxidation is one of the main causes of beer flavour instability. Oxidative reactions are a major cause of beer turning 'aged'. This is why breweries go to great lengths to avoid any unnecessary oxygen pickup during brewing, and why good bottling practices are so important.

Beer flavour stability may be influenced by a number of factors, but it is generally discussed in the context of the influence of raw materials and the brewing process. Malt, the brewing raw material used in large quantities, contains a variety of staling precursors, including amino acids, lipids, and aldehydes. On the other hand, malt is a rich source of endogenous antioxidants, which inhibit the rate of oxidation reactions.

During storage, beer flavour changes as a result of an increase in the amount of several compounds, among which the most significant are carbonyl compounds mainly generated via oxidation of higher alcohols, autoxidation of unsaturated fatty acids, enzymatic degradation of unsaturated fatty acids, Maillard reactions, and oxidative degradation of isohumulones.

Over the course of beer ageing, a decrease in bitterness and the appearance of typical ageing aroma attributes (sweet and cardboard-like notes) are observed. A significant decrease in bitter iso-α-acids during beer storage has been observed, depending on the storage conditions (light, temperature).

The nature of the changes that occur during the ageing of the product and the formation of new flavours and aromas in beers is quite complex and depends on the type of beer, the oxygen concentration present in the packaging, the presence of light, and the storage temperature.

In general, beer ageing results in a decreased bitter taste, increased sweet taste, and increased caramel, ribes (black currant), and toffee-like aromas. Carbonyl compounds such as trans-2-nonenal (cardboard aroma) form during beer storage from the oxidation of fatty acids and have been attributed to aged-beer flavour due to their very low flavour thresholds.

The ingress of oxygen during all stages of brewing and maturation should be limited to ensure that beer maintains maximum flavour shelf life (up to 52 weeks). However, even under reduced oxygen conditions, non-oxidative flavour modification reactions such as esterifications, etherifications, Maillard reactions, and glycoside and ester hydrolysis may still occur in bottled beer.

The colour modification is one of the most important beer ageing indicators, mainly due to oxidation and consequent degradation of polyphenols and the formation of Maillard compounds during storage, especially at warm storage temperatures.

Overall, the flavour and aroma of beer change over time, with a decrease in bitterness and fresh flavour notes, and an increase in ageing and vinous notes. The extent of these changes depends on various factors, including the type of beer, oxygen concentration, light exposure, and storage temperature.

Beer's packaging and storage conditions affect its longevity

The packaging and storage conditions of beer can have a significant impact on its longevity.

Packaging

Canned beer generally has a longer shelf life than bottled beer. This is because cans offer better protection from light exposure and oxygen, which are factors that contribute to beer spoilage. Canned beer can last for 1-2 years, whereas bottled beer typically has a shelf life of 6 months to 2 years, depending on the type of bottle and storage conditions. Amber and green bottles offer better protection from light than clear bottles, and darker bottles block out ultraviolet rays, which can cause beer to spoil more quickly.

Storage Conditions

Storing beer in a cool, dark place, such as a refrigerator, can help extend its shelf life. The ideal temperature range for storing beer is between 34-55°F (1-13°C). Beer should also be stored away from direct sunlight and heat sources to prevent spoilage. Additionally, it is recommended to store beer in an upright position to limit air contact and slow the rate of oxidation.

Beer Styles

Not all beers have the same shelf life. Hoppy beers, lagers, and ales typically have a shorter shelf life, while darker or aged beers, such as stouts, porters, barley wines, and Belgian ales, can last longer. Beers with a low alcohol content generally have a shelf life of up to 6 months, while those with a high alcohol content can last for up to 1-2 years.

Expiration Dates

It is important to note that the expiration dates on beer are typically "best before" dates rather than "use by" dates. This means that the beer may still be safe to consume after the expiration date, but the quality may start to deteriorate. However, drinking expired beer may result in an unpleasant taste due to exposure to light and air.

Beer's type and ingredients determine its shelf life

While beer doesn't become unsafe to drink past its best-before date, its flavour, aroma, and quality will change over time. Beer is made from various ingredients, and the type of beer will determine how long it lasts.

Beer Ingredients

Beer is made from four basic ingredients: water, yeast, malted grain, and hops. The quality of these ingredients will affect the shelf life of the beer. Beers made with fresh, high-quality ingredients will last longer.

Beer Types

Different styles of beer have varying shelf lives. Generally, lighter styles like lagers and pilsners have shorter shelf lives, whereas stronger ales, stouts, porters, and high-alcohol content beers can mature and improve with time. Hoppy beers, like IPAs, are best consumed fresh to enjoy their full flavour and aroma.

Packaging

The type of packaging also plays a crucial role in a beer's shelf life. Canned beer tends to have a longer shelf life than bottled beer as cans protect the beer from sunlight, which can degrade the flavour over time. Bottles have seals that can wear down over time, allowing air to get in.

Pasteurization

Mass-produced beer is often pasteurized, which extends its shelf life. Craft beer is mostly unpasteurized and made in smaller batches designed to be drunk within a certain time frame for the best taste.

Storage

Beer should be stored at a consistent temperature between 45°F and 55°F (7°C-13°C). Avoid drastic temperature fluctuations, and keep the beer in a dark place or in opaque containers to prevent "skunking," which is caused by UV light exposure. Store the beer upright to minimize oxidation, and keep it in a cool, dry, and vibration-free environment.

Beer's freshness can be assessed through smell, taste, and appearance

Beer is a perishable item, and its freshness can be assessed through smell, taste, and appearance. While it may be safe to drink beer past its best-before date, the flavour and quality will likely deteriorate over time. Here are some signs to look out for:

Smell

Unpleasant odours can indicate that your beer has gone bad. Common off-flavours include:

• Acetaldehyde, which smells like green apples
• Butyric acid, smelling like baby vomit
• Diacetyl, resembling buttered popcorn
• Dimethyl sulfide, reminiscent of canned corn or cabbage
• Hydrogen sulfide, giving off a rotten egg scent
• Mercaptan, with a skunky, rotten vegetable, or drain-like odour
• Metallic scents
• Oxidation, characterised by a cardboard-like smell

Taste

Tasting your beer can also help determine its freshness. Off-flavours may manifest as:

• Rancidity or sourness
• Unpleasant sweetness
• Bitter, spicy, or herbal notes
• Musty or mouldy flavours

Appearance

Visual inspection is another tool to assess beer freshness. Look out for:

• An excessively "squishy" can when squeezed
• Rust or flakes in the beer
• Bulging or pierced cans or bottles
• Discolouration or cloudiness
• Floating particles or sediment

While these signs do not necessarily indicate that the beer has gone bad, they may suggest that the quality has diminished, or that the beer has been exposed to unfavourable conditions.

Frequently asked questions