Before anyone commits to a container of green coffee, a small bag travels first. Green coffee samples are how buyers and sellers get to know each other: the seller says “this is what we have,” and the sample has to prove it. A good sample can start a relationship that lasts for years. A misleading one usually ends it on the first shipment.
Sending samples to buyers is a regular part of our work in North Sumatra, and we’ve seen what helps buyers decide quickly and what slows everything down. This guide covers the different types of green coffee samples, how much to ask for, how to evaluate what arrives, and the questions worth asking your supplier.
Green coffee samples at a glance
| Typical size | 200–350 g per lot for grading and cupping |
| Main types | Offer, pre-shipment, arrival, spot |
| What to check | Moisture, smell, color, defects, screen size, cup quality |
| Moisture target | Around 10–12% |
| Defect count basis | 300 g (Indonesian SNI) or 350 g (SCA) |
| Golden rule | Always cup before you buy, whatever the grade |
Why green coffee samples matter so much
A grade on an offer sheet tells you about defects you can see. It doesn’t tell you how the coffee tastes, how it will roast, or whether it suits your blend. Only a sample can do that.
For roasters, the sample answers a simple question: is this coffee worth the price, and does it belong on my menu? For producers and exporters like us, it’s the best chance to show what a lot really is. That’s why sampling is honest work. Pick the nicest beans off the top of a sack and you’ll win the first order, then lose the buyer when the real shipment arrives.
It’s also why samples keep coming up at different stages of a deal. The first one helps you choose a coffee. Later ones confirm that what’s being shipped matches what you approved.
The main types of green coffee samples
You’ll hear a handful of names in the trade. They aren’t complicated once you see where each one fits in the buying process.
| Sample type | When it’s sent | What it’s for |
|---|---|---|
| Offer sample (type sample) | Before you buy | Shows the quality and profile of a coffee being offered, so you can decide whether to buy |
| Pre-shipment sample (PSS) | After the contract, before loading | Drawn from the actual lot being shipped. You approve it before the container leaves |
| Arrival sample | When the coffee reaches your warehouse | Checks the coffee survived the voyage and still matches the PSS |
| Spot sample | Any time | Represents coffee already sitting in a warehouse near you, ready to buy and collect |
| Fresh crop sample | Early in the harvest | A first look at the new season’s coffee |
| Subject to approval (SAS) | Under certain contracts | The deal depends on you approving the sample. If it doesn’t meet the agreed quality, you can reject it |
How much should you ask for?
For a first look, 200–350 g per lot is the norm. That’s enough to measure moisture, count defects, sample roast and cup with a few people. The Specialty Coffee Association’s green grading uses a 350 g sample, while Indonesia’s national standard counts defects in 300 g, so a sample in that range covers both.
If a coffee passes that first round and you’re planning a large or regular order, it’s worth asking for a few kilos so you can test it on your production roaster. A coffee can behave differently in a 15 kg drum than in a sample roaster.
Ask for one sample per lot rather than a mix. If a supplier offers you three Mandheling lots, three bags tell you much more than one blended bag.
How to evaluate a green coffee sample
Every roaster has their own routine, but most good evaluations follow the same order: check the raw beans first, then roast, then taste.
- Check the label. A useful sample comes with a lot number, origin, process, grade, crop year and ideally a moisture reading. If it arrives with none of this, ask.
- Look and smell. Open the bag and smell it straight away. Fresh green coffee smells grassy or a little like hay. Musty, sour or chemical smells are warning signs. Look at the color too: it should be even across the beans.
- Measure moisture. Aim for around 10–12%. Much higher and the coffee risks mold during shipping and storage; much lower and it can taste flat or papery. If you have a meter, water activity tells you even more about how stable the coffee will be.
- Count defects and check screen size. Weigh out 300 g or 350 g, pick out black, sour, broken and insect-damaged beans, and run the rest through screens to check bean size. Compare your count with the grade on the offer.
- Sample roast. Roast to a light-medium level so the coffee’s own character shows. Let it rest for at least 8 hours before cupping.
- Cup it. Cup several bowls from the same sample so one odd bean doesn’t skew the result, and have more than one person taste if you can.
- Keep a portion. Hold back some green and roasted sample. When the pre-shipment and arrival samples come in, you’ll want something to compare them against.
Cupping is the heart of it. If you’re new to the process, the basics of coffee cupping are simple to learn, and our guide to cupping and quality grading explains how professional buyers score what they taste.
Why moisture deserves extra attention
Green coffee absorbs and loses water from the air around it. That affects more than mold risk. A 2023 study on green Arabica in the Journal of Microbiology, Biotechnology and Food Sciences by Demianova and colleagues found that moisture content and water activity move closely together, and that both are linked to how firm and brittle the beans are. That brittleness changes how a coffee behaves in the roaster, which is one more reason to know your numbers before you plan a roast profile.
Once you’ve bought, the same rules apply in your warehouse. Our guide to coffee storage covers how to keep green coffee stable after it lands.
A note on Sumatran samples
If you’re sampling coffee from Sumatra for the first time, don’t be put off by the color. Most Sumatran Arabica is wet hulled, which gives the green beans a darker, slightly bluish tone. That’s normal, not a defect. We explain why in our guide to Sumatra Mandheling coffee.
Questions to ask your supplier
The sample is only half the picture. The information that comes with it matters just as much. Before you approve a coffee, it helps to know:
- Which lot is this sample from, and how much of that lot is available?
- When was it harvested and processed?
- What process was used, and where was it dried?
- What grade is it, and how many times was it hand sorted?
- Will the pre-shipment sample come from the same bags you’ll ship?
- How will the coffee be packed: jute only, or with a liner such as GrainPro?
A supplier who answers these easily is usually one who knows their coffee. If you’d like the background on how processing shapes what you taste, our overview of coffee processing methods is a good starting point.
Common mistakes to avoid
Judging on grade alone. Grade 1 means few visible defects. It doesn’t guarantee a great cup.
Cupping a single bowl. One bad bean can ruin one cup. Several cups give you a fair picture.
Skipping the pre-shipment sample. It’s tempting when you trust a supplier, but it’s the only sample that comes from your actual coffee.
Not keeping a reference. Without a retained sample, you have nothing to compare the arrival coffee against if something seems off.
Leaving samples in the bag for weeks. Green coffee keeps reasonably well, but a sample sitting in a hot office isn’t a fair test. Evaluate it soon after it arrives.
Requesting samples from us
We’re a green coffee exporter based in North Sumatra, and samples are the usual first step with every new buyer. Through our sample form you can ask for any of the coffees we currently supply:
- Arabica Mandheling, North Sumatra
- Arabica Gayo, Aceh
- Arabica Lintong, North Sumatra
- Robusta Sumatra, see how it compares in Arabica vs Robusta
- Roasted beans
| Item | Details |
|---|---|
| Sample size | Around 300 g per coffee |
| Cost | Please ask when you request |
| Shipping | International courier from Medan |
| Order sizes we handle | From under 600 kg up to full containers |
| Packing for orders | 60 kg jute bags |
| Loading port | Belawan, Medan |
Tell us roughly how much coffee you need and what you’re roasting for, and we’ll suggest the lots most likely to fit. You can see full details on our Coffee Offerings page.
Ready to cup Sumatran coffee?
Tell us which coffees you’d like to try and we’ll get samples on their way from Medan.
Frequently asked questions
What is a green coffee sample?
It’s a small amount of unroasted coffee, usually 200–350 g, that a seller sends so a buyer can check its quality before buying. Buyers measure moisture, count defects, roast it and cup it.
What is a pre-shipment sample?
A sample taken from the actual bags being loaded into your container, after you’ve agreed to buy. You approve it before the coffee ships, so it’s your last check before the coffee leaves origin.
How much green coffee do I need for a sample?
200–350 g per lot is enough for grading and cupping. If you want to test a coffee on your production roaster, ask for a few kilos.
How do you evaluate green coffee?
Check the label and smell, measure moisture, count defects and screen size, then sample roast and cup it. Cup several bowls and, if possible, taste with more than one person.
What moisture level should green coffee have?
Around 10–12%. Higher moisture raises the risk of mold, while very dry coffee can taste flat.
Why do Sumatran green beans look bluish?
Most Sumatran Arabica is wet hulled, meaning the parchment is removed while the bean is still damp. The bean then dries exposed, which gives it that darker, bluish-green color. It’s normal.
CV. Buah Berdikari is a coffee trading and exporting company based in North Sumatra, Indonesia. We source Arabica and Robusta green coffee from North Sumatra and Aceh and help roasters and importers find the lots that fit what they’re making.