It all started with a pretty benign suggestion.

Bob Fulmer mentioned the long history of Alfred Klein and coffees from Finca San Carlos to me in passing, and dropped a line introducing us. What followed, over the course of a few weeks, was an exchange totaling over 5000 words and eventually filling numerous blog posts (you can check out Part I, Part II, and Part III. I hope to have more in the future).

You might note a casual comment at the end of Part III, from one Peter Baker. More than just an interested reader, Dr. Baker is a climate and coffee expert and the scientific adviser on the board of Climate Edge, a UK based climate monitoring outfit focused on smallholder agriculture. A quick salvo of emails later and I was a fly on the wall of on one of the most fascinating and fast-paced conversations I’ve been privileged to witness.

Installing Climate Edge’s NEXO in Santa Elena, Honduras

Mayra and Lowell of our beloved Catracha Coffee Project in Honduras are now equipped with Climate Edge technology, and should have some pretty interesting results of their own in short order. Lowell connected Peter Baker to our longtime partner in Guatemala, Jose Alejandro Solis, who manages the production of coffee at Finca Huixoc and Finca Injertal. With a few years of Alejandro’s data from the meteorological station on Finca Huixoc, Peter put together a preliminary report.

I asked Alejandro and Peter to let me share their findings. Alejandro summed up the relevance pretty succinctly:

I think your customers need to know what coffee farmers are facing these days. With unpredictable and unstable weather, the risks of producing coffee have increased. Flowering, planting, fertilizing, harvesting, and all other labors are greatly influenced by weather… and of course quality. So I think this topic is always important for everybody to learn.”

Disclaimer: this work is not Royal Coffee’s. It was produced using data meticulously gathered and organized on Finca Huixoc by Jose Alejandro Solis, compiled and analyzed by Climate Edge’s Peter Baker.

Some of the reasons monitoring meteorological data is important have to do with the ever-changing nature of climate conditions. Peter asserts that in addition to a 1°C rise in global temperatures in the last generation, many local climates (temperature, rainfall patterns, etc.) may be changing due to deforestation and other recent factors, making traditional local knowledge and advice outdated or unreliable.

Fortunately, excellent data collection practices at Finca Huixoc have enabled Alejandro and Peter to quickly gather a lot of important information about the kinds of challenges present in the precise microclimate on the farm in western Huehuetenango, Guatemala.


Summarizing climate data can be tricky. Usually the bulk of information is so vast that making sense of it can take a lot of time and energy, and summarizing it in too broad of strokes can overlook key details. Below, a summary of the monthly averages is graphed on a “Climogram” that looks at the ranges of temperature and rainfall.



It looks a little chaotic, because it is. The wild designs made by rainfall and temperature patterns on Finca Huixoc present an immense challenge. You can see that weather on Huixoc vary greatly from month to month and year to year.

To compound this, climate on Huixoc is much less predictable than other coffee growing regions like nearby San Martin Jilotepeque in Central Guatemala, or in an “ideal” zone like Jimma, Ethiopia, where coffee evolved to grow in the wild.



What does all this mean for Alejandro’s coffee?

Well, with regard to rainfall, coffee can usually tolerate about three months of dry weather, up to five with deep roots and good soil moisture retention. Alejandro’s farm experiences about four such dry months. However, his rainy months can be very rainy and sometimes concentrated in just one month. Peter Baker suggested that ground cover both during dry and rainy times can help mitigate the effects of such extremes in precipitation. He’s seen success with a mix of mulching and live grasses in similar circumstances.

Finca Huixoc also experiences some pretty high temperatures during two months of the year, above 30°C (86°F). It’s useful to look at the daily highs and lows (below) to understand this, because the averaged results in the climograms can disguise peaks and valleys.



Prolonged exposure to high temperatures can cause declining photosynthesis in the plants, and temperatures over 34°C can abort flowering in coffee. Higher elevations (the meteorological station is at 1410 masl, but the farm reaches nearly 1700) and shade may help decrease these harmful temperatures. Shade trees, for example, can reduce high temperature peaks and also insulate against risky lows.

However, air temperature alone isn’t the whole picture. Soil temperature, too, can present risks for coffee plants. Roots can die at temperatures in the soil above 32°C, and organic matter in the soil that provides nutrients for the coffee plants breaks down faster at high temperatures.



Soil analysis at Huixoc demonstrates the dramatic differences between covered (orange) and uncovered (blue) soil temperatures throughout a year, reaching dangerously high temperatures during early summer of 2017 without cover, but staying within the safe range under shade and mulch.

As with so much in coffee, answers aren’t always simple. Shaded air and soil temperatures look ideal, but the type of shade matters, too. Peter suggests that tall shade might be more beneficial than short, allowing more lateral sunlight during morning and evening, when air temps are cool. He also notes that slope direction may play a major role in coffee development, as western-facing mountainsides, at least in the case of Huixoc, may shade early morning sun during critical times during the year when the plants ought to be maximizing their photosynthesis.

Peter and the team at Climate Edge introduced another variable I hadn’t heard of before: vapor pressure deficit. In many cases, those observing climate will record relative humidity. But when plants deal with changes in humidity and temperature, they constrict their stomata (breathing holes in the leaves), which slows down photosynthesis. Thus, measuring the water in the air as a vapor pressure deficit, rather than a relative humidity, can be more useful in understanding the health.

As VPD increases, plants can dry out. Climate Edge recommends maintaining VPD readings below 2.0kPa (kilopascals of pressure). The graph below illustrates the VPD interpretations of data from Finca Huixoc (blue, in the middle), under temperature (grey) and above rainfall (blue, on the bottom). Note that the VPD graph is inverted, that is, a high VPD reading displays as a downward spike in the middle graph.



The red dotted line in the center represents Climate Edge’s recommended limit, and as you can see Finca Huixoc experienced a number of days in spring and summer of 2015 that exceed the recommendation, before the relief of rains that ended the warm dry season.

Like so many other Central American coffee farms, Finca Huixoc suffered from a severe coffee leaf rust (roya) outbreak. A July 2015 survey of the farm gave no warning that by the following month significant percentages at multiple elevations would be hit by the fungus. Rust tends not to spread under 18°C, so the highest elevations of the farm were somewhat insulated from the problem due to lower nighttime temperatures.



So, where does this leave Alejandro Solis? With a wide range of elevations and microclimates, even ideal conditions would present challenges for farm management. But Finca Huixoc must struggle against high air and soil temperatures, low humidity (high VPD), and coffee leaf rust. Combine this with predicted local temperature increases and drought conditions, and Alejandro faces a formidable uphill battle.

Alejandro’s farms are some of our most consistent, excellent tasting high grown Guatemalan coffees. It’s clear, with such a comprehensive picture of his farm and climate data, that Finca Huixoc doesn’t simply make great coffee happen by chance. Concentrated efforts, preventative measures, specific solutions for both short and long-term challenges paint a picture of a farm dedicated to scientific analysis and sustainability.

I’m grateful to Peter Baker of Climate Edge and Alejandro Solis of Finca Huixoc and their teams for the work they’ve done and the permission to share it here. Look for more climate reports, as Climate Edge works with farmers around the world, including the Catracha Coffee Project in Honduras.