Testing Kagera Robusta in an Espresso Blend: A Blank Trial Record

To test Kagera robusta in an espresso blend, compare a defined base with weighed blend variants, record the roast and brewing conditions, and decide against your intended drink. Start with separately roasted components so you can change the blend ratio without roasting every combination again. A trial can support a decision about the tested lots; it cannot establish how every Kagera robusta will perform.

What should the blend trial answer?

Write one question before choosing ratios: does this robusta lot help the base meet the requirements for our intended espresso drink? Name the drink, the qualities you want to assess and any unacceptable characteristics. If the product is served with milk, include that preparation in the plan and record the milk and amount. Leave the result blank until someone evaluates it.

Sweet Maria’s blending guidance recommends knowing the components and defining a goal before blending. Its separate-roast approach is useful for experimenting with proportions. Hacea’s published robusta trials concern particular coffees and equipment; their temperatures, tasting notes and suggested percentages are not evidence for a Kagera lot.

Define the base and the ratio basis

Give each component a lot ID and roast batch reference. If the base contains several coffees, record its recipe and version. For a first comparison, keep those internal base proportions fixed while changing its share of the finished blend. Otherwise a change in the base recipe becomes another possible explanation for the result.

For this worksheet, percentages refer to roasted bean mass at blending. Keep green input weights and roast output weights in separate fields. A green blend percentage and a roasted blend percentage describe different stages; do not swap their labels. This record is an editorial tool for your roastery, not an Afri Exports operating procedure or a standard test method.

How do you calculate a trial blend?

Multiply the total roasted blend mass by the component percentage divided by 100. Hypothetical arithmetic only: a 200 g blend containing 10% robusta uses 20 g roasted robusta and 180 g roasted base. A base-only control uses 200 g of the same base. These numbers illustrate the calculation; they are not a recommended robusta percentage, sample quantity or prediction of cup performance. Choose enough material for your own planned evaluations and repeats.

Keep the comparison interpretable

Choose the ratios before tasting, including a base-only control. Record the separate roast profiles, roast dates, storage and elapsed time to evaluation. Use coded cups and record the serving order if you want evaluators to assess samples without seeing the recipes. Keep the code key with the trial record.

For the first comparison, use one recorded brewing recipe across the variants and log any deviations. Include the machine, grinder, water reference, dose, beverage mass, extraction time and tasting conditions. If you then dial in each blend separately, record that as a second comparison with its own recipe settings. A preference after dial-in answers a different question from a comparison made at fixed settings.

Record observations in the evaluator’s own words, separately from the decision. Do not fill in expected body, crema, sweetness or bitterness in advance. If roast age, recipe or another condition differs, state the limitation and repeat the comparison where needed before treating it as a basis for a purchase.

Blank roaster blend-trial record

Copy these fields for each trial. The empty result fields are deliberate. This is an original planning record, not a completed test, supplier guarantee or purchase approval.

• Trial ID: ____; date: ____; owner/evaluators: ____; intended drink and preparation: ____; question: ____; decision criteria agreed before tasting: ____.
• Base recipe/version: ____; component lot IDs: ____; robusta lot ID and sample reference: ____; evidence or unknowns about the samples: ____.
• Roast references for each component: ____; green input mass: ____; roasted output mass: ____; roast date/profile: ____; storage: ____; elapsed time at evaluation: ____.
• Variant code: ____; base-only control code: ____; planned total roasted mass: ____; planned base/robusta percentages: ____; actual component masses: ____; actual total and percentages: ____. Repeat this row for each variant.
• Comparison phase — fixed recipe or individually dialled-in: ____; machine/grinder: ____; water reference: ____; dose: ____; beverage mass: ____; extraction time: ____; other recipe settings: ____; deviations: ____.
• Serving order and code-key reference: ____; repeats: ____; milk type and amount if used: ____; tasting time/conditions: ____.
• Observations by evaluator, code and repeat: ____; fit against each criterion: ____; disagreement or uncertainty: ____; confounding differences: ____.
• Decision — retain base / take variant to another trial / repeat / stop: ____; evidence and limitations: ____; next action, owner and date: ____; confirmation needed before production: ____.

What does a promising result allow you to conclude?

It identifies a candidate for further work under the conditions recorded. If your production plan blends green beans before roasting, run a separate production-method trial rather than assuming the separately roasted recipe transfers unchanged. Keep the production batch, roast and beverage evaluation linked to that recipe version. A different lot or base recipe needs its own evaluation.

Blend suitability and shipment acceptance are separate decisions. Use the sample comparison record for offer, pre-shipment and arrival evidence. Use the AA versus peaberry guide when selecting between those physical grades; this worksheet does not rank grades or replace a purchase specification.

Move from trial notes to a green coffee enquiry

Afri Exports supplies green beans, including Kagera robusta from Tanzania. Send the lot reference you evaluated, intended use, required quantity, destination and any unanswered specification questions. Ask for current lot confirmation before using the trial to support a purchase. No ratio in this guide confirms availability or a sensory result.