How long hops can be stored

This question has two very different answers depending on the source of the hops. Let’s start with pelletized hops sold to commercial breweries. These hops begin their journey at the farm, where tall bines are cut from the fields and the cones are separated using a picking machine. Although a small number of farmers now use hop combines that cut, pick, and separate leaves and bines from cones, most still use picking machines housed in buildings typically referred to as picking sheds. Once the picker has disassembled the cones, leaves, and bines, a system of belts and blowers separates out the cones.

The next step is hop kilning, where hot, dry air reduces the moisture content to below 8%. After kilning, the dried hops are stored in large piles to allow the moisture to equilibrate. In most parts of the world, the hops are then compressed into bales. Before pellets became the norm, this was the end of the line for most hops: Bales would be stored in warehouses — often warm ones — before being shipped to breweries. It was U.S. brewers who demanded refrigerated hop storage. In fact, U.S. hop processors routinely store bales in freezers, whereas German processors typically store them in refrigerators at 36–41 °F (2–5 °C).

Because most hops today are pelletized, bales destined for pellet production are usually stored only briefly before being broken apart using a piece of equipment called a bale breaker. The cones are then milled into powder using a hammer mill. The powder is typically blended in a ribbon-style mixer to reduce variability between bales, then compressed into pellets using a forming die. These days, forming dies are cooled with liquid nitrogen and some processors even cool the hop powder prior to forming. Finally, the pellets are packaged in foil bags. The current standard is to flush these bags with nitrogen gas to create a modified atmosphere that reduces oxidation during storage. For many years, vacuum packing was common, but this method makes the bags prone to damage and can cause pellets to clump together into hard-to-handle masses.

The foil bags of hop pellets are then boxed, palletized, transferred to cold storage, and kept there until shipped to breweries or into distribution channels. Depending on the variety — some hops have better storage properties than others — and the intended use, hop pellets can be stored cold for up to six years. In general, pelletized aroma hops start to fade after 2-3 years of storage and bittering hops can hold their brewing value up to about six years. Breweries equipped with lab instruments and trained sensory panels routinely sample and analyze their inventory to determine how best to use it. Because hops are used exclusively in beer, breweries contract with growers to ensure a reliable supply. When aroma hops become unsuitable for brewing, brewers may repurpose them for bittering or take the loss. One major advantage of hop extracts is extended shelf life, which is why many larger breweries convert a portion of their inventory into extracts shortly after pelletizing (most extract facilities are designed to process pellets, which are more compact than cones).

I know I haven’t answered your question yet, but it’s important to understand how pellets are produced and packaged. The issue is this: Pellet bags typically contain 11, 22, or 44 pounds (5, 10, or 20 kg) of hops. Hops sold in the homebrewing market, by contrast, usually come in 1-oz. (28-g) packages. So the obvious question is: How are these 1-oz. (28-g) bags produced?

Typically, they are repackaged from larger bags that are labeled with critical information such as the harvest year, the processor (the company that converts bales into pellets), a lot number, and sometimes a QR code linking to hop analytics. However, not all repackaged pellets retain this vital information. For example, a commercial-sized bag of 2024 Cascade hops labeled with 8.5% alpha, 6% beta, and 1.5% oil might simply become a bag labeled “U.S. Cascade Hops” with a general alpha acid range of 5–9%.

Hops sold to homebrewers are somewhat analogous to growlers or Crowlers^TM of beer. While it is entirely possible to repackage hops without increasing oxygen exposure, the risk is higher. This alone likely shortens the shelf life of homebrew hops compared to those sold to commercial brewers. Another issue is the packaging. Foil bags offer excellent gas barrier properties assuming the seal is perfect and there are no pinholes. Plastic bags, on the other hand, offer poor barrier protection, meaning that even a vacuum-sealed plastic bag can still allow oxygen ingress over time.

My advice is to use hops as soon as possible after purchasing, unless they are packed in foil and clearly labeled with the crop year and processor. The challenges of repackaged hops are well understood, and many hop processors serving the homebrew market have responded by labeling their products with the same information as packs sold to commercial brewers.

Hops do go on sale, and good deals can be found. I love a bargain and feel confident buying discounted hops if I know they were packaged by a reputable processor and properly stored throughout their life. That last piece, storage history, is nearly impossible for any buyer to verify, whether homebrewer or pro. That’s why it’s good brewing practice to smell your hops before use. If you open a bag and something seems off, it’s your call: Repurpose the hops for bittering or make the executive decision to toss them.