Coffee Harvesting with Machines: Newer Methods in Brazil Coffee Production

Mechanical harvest methods are used in large parts of Brazil, on all scale of coffee farms.

By and large, Brazil must innovate in their coffee production techniques; they can’t afford not to. The price one would need to produce coffee in Brazil as it is picked and processed in Ethiopia, or Kenya, or Guatemala, or Sumatra, would be far higher that the quality of the cup is truly worth. There is simply not the available low-cost labor to do this job in most coffee areas of Brazil, nor willing workers. Fortunate for laborers, they have options.

This means that Brazil needs to turn to innovation and technology. These techniques might seem like a vast departure from the way other regions attain a resulting coffee with high cup quality. In a sense, it requires some blind faith to see how these methods might work at all.

Mechanical coffee harvester machine in Brazil
Mechanical coffee harvester machine in Brazil

A machine harvester at rest in the Cerrado area of Minas Gerais

Robots and Coffee: Mechanical Harvesting

The shock for a traveling coffee buyer on their first trip to Brazil would be to see coffee fruit, from raw green, to semi-ripe to over-ripe and dried pods, all picked and piled up at once. The basic Brazil technique is different than every other origin where hand-selection by the picker is a key of quality. In Brazil, they “pick it all, sort later”.  On flat farms, which predominate areas like Cerrado or Mogiana, large mechanical harvesters engulf the tree, which are planted in neat rows. Several cylinders “beat” the coffee off the tree, which leaves a good portion of the firmly attached under-ripe green fruits on the branch. They are strip-picked by hand later.

Tractor collects the coffee from the machine harvester on a farm in Cerrado area.
Tractor collects the coffee from the machine harvester on a farm in Cerrado area.

There are also small hand operated “harvesters” using the chassis of a gas weed wacker, which vibrate the coffee off the tree. This has the advantage of allowing a picker to harvest the top, middle, inside or outside of the tree, depending on which zone has the most ripe cherry. At least in theory it does, and frankly I have never seen these in widespread use. It matters little if it is hand-picked or the machine is thrashed by the whip-like tendrils of a harvesting machine. Most hand-picking is strip-picking: they take all the cherries off the tree at once. Where there is selective hand-picking, to a coffee buyers eye, it matters little. It’s not at all as one might see in a country like El Salvador, which an abundance of red-to-crimson fruit.  Selective picking in Brazil might involve 2 or 3 passes to over time to harvest the coffee cherry, but a look at the bags shows a wide mix of ripeness levels.

Rapid Harvesting Practices

The farm manager in Brazil will time the harvesting to the day when each branch of cherry has the least green fruit, and the dried pod cherries are not so aged they are dropping to the ground, or molding on the tree. On a first Brazil coffee trip, a buyer might be surprised that coffee dries on the tree

Aside from abandoned farms, this is not seen in other places, and is partly due to the dramatic, dry climate in most Brazil coffee regions (aside from Bahia and Matas de Minas), as well as the fact they intentionally want to keep the coffee on the tree until the best moment to harvest it in one pass.

Coffee cherry quality, low and high quality
Coffee fruit: Strip picking in Brazil versus hand selective picking in El Salvador.

The raw material that goes to the wet mill is completely different in Brazil than other regions, such as Central America. Strip picking in Brazil versus hand selective picking in El Salvador. Before jumping to conclusions though, the resulting coffees both scored on par with each other.

Unripe coffee cherry and yellow variety ripe coffee brazil
Tree-dried coffee, unripe green cherry, and yellow variety ripe cherry all picked at once by machine.

Coffee entering the wet mill, in which the tree dried boia coffee is floated out straight away. While this coffee has many immature cherries, it is mostly a Yellow Bourbon lot so the ripe coffee is not red.

In any case, they use the equipment at the wet mill and dry mill to sort out the under-ripes and over-ripes. There are 3 basic separations that result: dried coffee “pods”, ripe coffee, and under-ripe green cherries.   The dried pods generally float, and can be removed with a water bath as a first step in the wet mill. This coffee can be put directly on the patio to complete the drying, and later it will be husked in one step to reveal the green bean, ie. the dry-processing method

Green and part green unripe coffee, with many defective floaters too, Brazil
Green and part green unripe coffee, with many defective “floaters” too, Brazil

Under-ripe coffee fruits are visually stunning, but make for an awfully astringent cup of coffee.

The under-ripe coffee is separated from ripe coffee by the pulper that peels off the fruit skin, or in some cases by the traditional “criba” drum. Both these function by way of the distinct difference in hardness between a ripe and unripe coffee cherry.  The unripe green fruit is rock hard, and even with the application of friction, the skin will not separate from the nascent mucilage layer. The mucilage of the ripe fruit has softened and the skin can be peeled away.  In the case of the “criba”, the green fruit will not pass between the slats in the rotating drum, and is washed out the end by a flow of water, where the ripe fruits pass through into a separate pulper.

Underripes, what would roast up as “quakers”, are separated to be sold for institutional grade coffee or “local consumption.” Which touches on one of the great oxymorons of coffee: If you want really bad coffee, go to a country that grows it. traditionally the bad coffee is kept in-country since coffee has essentially been a cash crop. That is changing in Brazil, but only on a small scale at and at a handful of shops and roasteries, many in Sao Paulo.

Centriflux coffee spinner to remove excess moisture from coffee before it goes to the patio, Brazil
Centriflux coffee spinner to remove excess moisture from coffee before it goes to the patio, Brazil

A salad spinner principle applied to coffee… Some mills are running wet coffee coming out of the wet mill and bound for the drying patios through a centrifuge. It removes excess water from the coffee and ensures faster, more even drying in the sun.

Motorcycle used to turn over the coffee on the Patio, Brazil
Motorcycle used to turn over the coffee on the Patio, Brazil

Other ways to save labor in coffee processing include bicycles and motorcycles adapted for raking coffee. In other Latin countries this is done by worker hauling heavy wood rakes over the coffee to rotate it and ensure even drying. But why walk when you can ride?

The Dry Mill Solution (Machines Work for Cheap)

Few countries put as much stock in the operations at the dry mill to further remove problem beans. They use the same methods as found elsewhere, namely “density tables” that can separate light-weight coffee, electronic color sorting to catch yellow or white beans and immatures, and screening machines to separate small beans and broken pieces.

Color sorting optical machines for coffee, Brazil
Color sorting optical machines for coffee, Brazil

Machine color separators are used in many dry mills worldwide, but without hand selection in harvesting or hand sorting in the dry mill, Brazil relies on them remove defects and improve cup quality

But other origins use this as refinement in a system where they have not allowed much “bad” coffee cherry to enter. They are assuming the cost to get unripes and over-ripes, floaters and black beans, out of the general pool of good coffee is much more expensive than having their pickers select only ripe coffee to begin with.  In many countries, pickers will re-sort the coffee cherries at the mill as well, before turning them in. But Brazil refutes the old acronym GIGO (Garbage In, Garbage Out), and relies on the equipment to burnish the quality that starts with rather trashy coffee picking

Harvesting coffee by cutting off the entire coffee tree branch, Brazil
Harvesting coffee by cutting off the entire coffee tree branch, Brazil

Hacking the coffee trees to the trunk with large gas shrubbers. This is pruning and harvesting all in one.

Even More Rambo-esque: Hacking the Harvest

On this trip I was exposed to an entirely new approach … jaw-dropping in fact. At this farm in Sul de Minas, they cut the entire branch off the coffee tree with all the fruit intact, and feed it into an oversized separator that shreds everything put into it, and ultimately removes the fruit from the sticks and leaves.  The process starts with 2 people working with long-bladed gas “shrubbers”. They lay down tarps between the trees, then methodically hack the top and branches to about 6 inches from the trunk. The remaining cherry on near the trunk is hand harvested later.  The branches are collected, tossed in a wheelbarrow, dumped into a cart attached to a tractor, and hauled to the movable “coffee separator”.

Hauling coffee tree branches pruned from trees to the tractor
Hauling branches pruned from trees to the tractor

Hauling the branches, loaded with coffee cherry, to the tractor, which takes it to the Separator.

Branches are fed in and leaves fly out the rear of the beast, as the coffee and sticks are separated with vibrating screens below. It’s much more like a tree-trimming operation that coffee harvesting; loud, and semi-dangerous with lots of sharp moving parts.  It also produces 6 bags of coffee cherry in about 10 minutes of work by the 15 person crew. This farm was formerly employing near 50 pickers to hand harvest the coffee.  The trees that have been trimmed to the trunk are allowed two years to recover before their next harvesting. In the first year, all the plants energy goes into growing new branches and leafs. In the second year, the coffee shrub is focused on producing an abundance of fruit.

The tractor backs up the Coffee Separator. The result is a few folks can yield 6 bags of coffee in a matter of minutes.

Better Volume, Lower Cost

The average yield in this area of Carmo de Minas is 25 bags of green coffee per hectare. This farmer is only harvesting half the farm each year, as the other half grows leaves and recovers. So the land is half as productive.

But with this method, he is yielding nearly 70 bags per hectare of coffee, perhaps because of the way this method channels the biannual cycle of production natural to coffee trees (high crop and low crop) and forces the plant to focus on one or the other; make leafs or make fruit.  With the higher volumes produced and smaller labor force, the farm can afford to pay workers better and invest in future harvests with good agronomy and equipment.  This method can be extended past the flat farms, which tend to be lower altitude and more volume-oriented, to the smaller farms in more vertical regions.

Coffee cherry is screened from other plant material below
Coffee cherry is screened from other plant material below

Leafs are shredded and blown out the back, sticks and coffee are separated on screens and the coffee ends up in bags below

A Soak for Dry Coffee

Another method I had not seen before  involved dry-processed coffee, which is typically laid out on the patio direct from the tree. These dried pods are called boia in Brazil, ball. In most areas of Brazil, this includes a high percentage of coffee that has already dried fully on the tree, or to a tough raisin-like level, but not completely dry.  At a farm that does no “forced demucilage” (cereja descascada) separation, or on one that only produces dry-processed coffee, this coffee might also include all the green unripes as well, a reason there are so many quakers in poorer natural Brazil coffees.

Double pass naturals ready to be pulped, Brazil coffee re-soaked in water
Double pass naturals ready to be pulped, Brazil coffee re-soaked in water

Tree-dried natural coffee is soaked 12-24 hours to soften the skin, then pulped by machine.

But on farms that put their boia pods through the wet mill, they are trying something else. They are soaking the already-dried fruits for one day in a water tank in order to soften the skin and mucilage layer. Then they are sending this soaked and not-so-dry coffee through the same pulper they use for standard ripe coffee, with the advantage of being able to sort out unripes, floaters or other defects. The farm I saw it at, Fazenda Serrado, calls it double-pass naturals.

In fact it is unlike a traditional natural where the long drying of the seed, surrounded completely by dried parchment, mucilage and skin layers, changes the dynamic of the coffee. As it dries, there is a transfer between the bean and its environment, although most of this is moisture leaving the seed, not entering it.  In the double-pass natural technique, the coffee has had a considerable time drying with its full skin intact, on the tree. But it is laid out on the patio with the skin removed, and the darkened mucilage layer now all that is attached to the parchment shell around the green bean. How this affects the taste I am not sure. But the cup quality shouts out natural in all regards, and seems to be producing a sweet and uniform coffee in the vein of a typical dry-processed cup.

Pulp Natural Sertao coffee on the patio
Pulp Natural Sertao coffee on the patio

Inset – traditional natural pods (boia) coffee on the patio, verus pulped double-pass naturals

Other origins are achieving this result in a laborious hand method they can raisin coffee, where ripe cherries are picked and allowed to dry until the skin and mucilage is pruney and tough, but not a true dried pod. Then they are hand peeling the cherries, since it cannot be run through a typical pulper.  Given the costs involved, the price they look for from these lots doesn’t seem commensurate with the cup quality though. Maybe they should take a cue from Brazil: soak it.

— Thompson

2 Responses

  1. I have agriculture Back Ground & hired in one Fam located in ETHIOPIA ,I want to Know how to harvest coffee usining Machinery on state farme. Machinery used for pruning of coffee in state farm ,Croup water Management for coffee plant esp.usining Drip Irrigation.

    1. The best place to learn about machine harvesting is Brazil. You can look at the web sites for these machines online. Since we are coffee importers and retailers we don’t know a lot about the machines. Good luck!

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