For specialty coffee roasters, there is plenty of excitement associated with the arrival of fresh green coffee landing, and for good reason. When roasted properly, in-season green coffee can have vibrant, delicious flavours.
However, while it doesn’t degrade at anywhere near the same timeframe as roasted coffee, green coffee does lose quality as time wears on. This is why storing it properly is important, as it makes sure roasters can keep their green beans fresher for longer.
But what happens when the next fresh crop arrives, and there is still some of last year’s left over? What can we do with it?
This is known as past crop coffee. As freshness becomes a growing priority in the coffee sector, it has largely been ignored by specialty coffee roasters across the world, as it doesn’t have the same complexity and nuance as in-season green coffee.
But does it still have potential? Can it still taste good? And is there a way for roasters and producers to utilise it while still offering high-quality coffee that consumers will reliably enjoy? To answer these questions, I spoke to two coffee industry experts. Read on to find out what they said.
You may also like our article on growing sustainability in the coffee supply chain.
What is past crop coffee?
Joe Marrocco is VP of Coffee Sourcing and Product Development at FairWave Coffee Collective. He explains that technically, coffee can be defined as a past crop as soon as the fresh crop becomes available.
For example, if an importer receives an Ethiopia Yirgacheffe coffee in their inventory in April 2020, this coffee would be considered a fresh crop until April 2021 when the next year’s harvest lands. The Ethiopia Yirgacheffe that was received in April 2020 would then be considered a “past crop” coffee.
However, Joe adds that many roasters may mistakenly refer to a coffee as past crop simply because it is “past its prime” and presenting aged flavours.
“There can be a big communication breakdown when it comes to determining what is past crop and what is fresh crop,” he explains.
It’s therefore important for roasters to be mindful of harvest dates listed on importers’ offerings sheets. Furthermore, they need to have an understanding of the seasonality of different origins, as this will indicate age more clearly.
In recent years, past crop coffees have become more and more plentiful. During the Covid-19 pandemic, delays at ports and changes to purchasing commitments meant that more coffee than ever sat in warehouses and containers for extended periods of time.
How do they taste?
In many cases, buyers shy away from past crop coffees because of the perception that their flavour changes, specifically causing a drop in quality and the emergence of undesirable flavour notes.
Most of the time, this ageing occurs because of oxidation, specifically where lipids are concerned. This changes the aroma and flavour compounds within the green bean.
However, while past crop coffees are generally associated with a decline in flavour and quality, this can vary depending on exactly how its profile has changed.
“If the coffee holds up in some ways, you might not see too big a price change,” Joe explains.
Ian Fretheim is the director of sensory analysis at Cafe Imports, a specialty coffee importer based in Minneapolis, USA. He explains that he has been conducting ongoing research on the sensory profile of past crop coffee.
Ian explains that in particular, one of the most important aspects of his research has focused on the water activity in green coffee over time. Water activity (a metric that is increasingly used over moisture level) is a measurement of how something called the “vapour pressure” in green coffee stacks up against the vapour pressure in pure water.
Effectively, it is a measurement of how much water in each green bean is “free” and available to take part in chemical activity.
“One of the big things that comes out of water activity, in terms of downside risk for specialty coffee, is that high water activity gives the beans an increased rate of lipid oxidation,” Ian explains. “The end result is that you can get a prematurely agey-tasting coffee.”
Lipid oxidation leads to the formation of chemical compounds that can cause off-flavours. According to Ian, one of the primary chemical compounds developed when the lipids in green coffee oxidise is trans-2-nonenal. This is a compound that is often associated with flavours like wood, cardboard, cucumber, and unripe melon.
While the chemical compounds that create positive flavours are still present, Ian says the addition of these “negative” or undesirable compounds is what creates an “agey” flavour. The rate at which they do so will also depend on a number of factors, such as varying water activity levels and storage.
Ian also notes that not all past crop coffees have these agey flavours.
“We have tasted coffees from Ethiopia, Costa Rica, and Guatemala that have crossed the one-year mark and are definitely past crop, but are still cupping very well,” he says.
Roasting past crop coffee
More recently, Ian tells me his team have been looking into different roasting strategies that can be used to account for or even correct the agey flavours associated with past crop coffee.
Among other things, he recommends that roasters learn about the various compounds that affect coffee flavour, as well as the temperatures at which these compounds boil or melt.
With this information, Ian says roasters can technically “roast out” these negative compounds. However, he notes that this may mean roasting out desirable chemical compounds, too, and says that it’s all about balance.
“There is a sweet spot,” he suggests. “It’s where you have pushed through a lot of the agey flavour, but you haven’t quite begun carbonising or burning up the coffee’s structure.”
Ultimately, this means past crop coffees generally perform better with darker roast profiles. However, Ian says that how dark you go will depend on the coffee in question, and notes that preserving any remaining desirable flavours is important.
“You want to keep bitterness to a minimum while preserving acidity and preserving as much sugar as possible,” he suggests. “If you are a good enough roaster, you will still be able to deliver a very elegant cup of coffee.”
Past crop coffee: a fair reputation?
Generally speaking, coffees “become” past crop when they are still in the hands of exporters and importers.
If there is a market for them, it can be advantageous for roasters catering to customers who prefer darker roasts, where those undesirable flavours will be less present. They can also be great for blending, where other coffees will help to mask any agey notes.
In addition, if the coffee itself is traceable, certified, and sustainable, it will often be a great way to buy ethically-sourced coffee at a more competitive rate.
However, in order to help maximise the potential of past crop coffee, Joe tells me that the coffee industry must address the stigma surrounding the term.
“I think that a lot of companies in the higher end of specialty coffee look at past crop as a dirty term,” he explains. “Past crop coffees are not inherently bad, and there are plenty of places where a past crop coffee can be very useful. I believe that a really good roaster can take a past crop coffee and make it taste excellent.”
However, for roasters who only offer light roasts, or those who wish to highlight fresh coffees at their flavour peaks, there is no quick fix for hiding these negative, agey flavour compounds without going further into the roast.
“Maybe you’re not going to do a super light, micro lot style roast,” adds Joe. “However, you can present past crop coffees to a different audience. You can make them a lot more approachable both in roast and flavour profile, as well as in price.”
From my discussions with Joe and Ian, it’s clear that while the connotation is fair, past crop coffee doesn’t always have to taste inherently agey.
And even if these flavours are present, there are ways to soften or eliminate them during the roasting process, meaning there’s still plenty of utility, despite the lack of freshness.
For roasters, while they understandably may not be the first port of call, past crop lots can be an affordable way to find a new blender coffee or a high-scoring dark roast. Either way, you’ll never know until you try.
Enjoyed this? Then read our article on how to protect green coffee from excessive water activity.
Photo credits: Cafe Imports
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