But rising temperatures and worsening drought linked to climate change are now hitting production and fixing that may require moving many Ethiopian coffee fields uphill, experts say.
Aside from its cultural value, coffee is Ethiopia's single largest source of export revenue, worth more than $860million (R10.9billion) in the 2016-2017 production year.
But coffee-growing areas in eastern Ethiopia have seen the average temperature climb 1.3°C over the past three decades, according to the Environment, Climate Change and Coffee Forest Forum, an Ethiopian non-governmental organisation.
That has caused stronger drought and - given that coffee is a crop sensitive to both moisture and temperature - a worsening of diseases that afflict coffee berries.
As a result, thousands of hectares of coffee plants are being lost each year in traditional growing areas, which is raising fears about the future of Ethiopia's coffee production.
The country's government is now encouraging farmers to grow coffee at higher elevations - up to 3200m above sea level, about 1000 metres above the norm.
That could help mitigate some of the climate change pressures Ethiopia faces, said Birhanu Tsegaye, who heads extension services for coffee, tea and spices for the Ethiopia Coffee and Tea Development Marketing Authority (ECTDMA), a government body tasked with overseeing the sector.
As temperatures rise, “even areas not (formerly) suitable for coffee growing have become suitable, presenting an opportunity for the country to cope with climate change,” he said.
Pressures from warming conditions have been noticed in other parts of the country too.
Aman Adinew, chief executive of Metad Agricultural Development, which manages two large plantations in Oromia and SNNP regional states, said changing weather patterns in the country's south had affected exports.
The annual harvest, which normally takes place in November and December at his Hambela and Gedeb coffee farms, was delayed by a month, because the beans had not ripened, he said.
“Since the coffee beans were still green by the beginning of 2018 due to a shortage of rain, it led to a delay in coffee processing and export, effectively meaning breach of contract with our North American, Asian and European customers,” he said.
Around 90percent of Ethiopia’s coffee-growers are small-scale farmers, and the industry directly and indirectly employs up to 20percent of Ethiopia’s 100million population, ECTDMA said.
Exports in the 2016-2017 production year totalled just over 220000 tons, figures from the trade ministry show.
Coffee exports have fluctuated over the last five years, making it difficult to discern any downward trend, Tsegaye said.
But with the country adding tens of thousands of coffee hectares in new growing areas each year, that is offsetting many of the losses in traditional areas, he said.
Tsegaye said the government was also working to combat the effects of climate change in traditional coffee growing areas by offering small-scale farmers training on using shade trees to help hold down temperatures, and on irrigation and better crop handling after harvest.
He said the authority was also introducing hardier varieties of coffee, resistant to diseases and weather extremes.
However, Tsegaye admitted that current levels of assistance to traditional small-scale coffee farmers might not be enough to save the industry in those areas, which is why the coffee marketing authority is looking at growing coffee at higher altitudes.
Tadese Woldemariam, a technical adviser at the Environment, Climate Change and Coffee Forest Forum, said growing coffee in areas previously unfamiliar with the crop could work, but it needed to be done carefully - and could have side-effects.
“When traditional coffee-producing areas disappear, thousands of years of coffee-growing culture disappear,” he said.
“Highland areas of Ethiopia with little history of coffee production can be an alternative only if there are agricultural extension packages that make growing high-quality coffee sustainable,” he said.
He said Ethiopia was racing against time to save its coffee sector.
The areas of the country suitable for coffee production are shifting higher each year, he said, which means “by the end of the century most coffee-growing areas, especially those below 1500m above sea level, will no longer be suitable for coffee production.”
In places that has already happened, with some traditional coffee-growing areas, especially in the east, now covered in khat trees. The plant’s leaves, chewed by millions in the Horn of Africa, contain a psychoactive drug that is used as a mild stimulant.
While coffee is usually harvested once a year, khat - which is drought-tolerant - can be harvested three times a year.
Woldemariam said 60percent of Ethiopia’s traditional coffee-producing regions might lose the crop in the coming decades if climate change remains unchecked.
He urged quick action to save the crop, though warned shifting production to new areas could affect the quality and taste of the coffee.
The government is looking at how to begin selling to new markets as new coffee varieties are planted and begin to fill the gaps created by what may be the gradual disappearance of some Ethiopian varieties, such as "Harar" coffee, which is particularly at risk.