Blending
Sources: The Coffee Roaster’s Companion by Scott Rao (2014); El Arte del Café by Sébastien Racineux & Chung-Leng Tran (Lunwerg, 2017)
Blending combines roasted (or green) coffees from different origins, varieties, or processing methods to create a flavor profile that does not exist in any single component. Blending is the historical norm in commercial coffee; single-origin coffee is a specialty-market development. (source: The Coffee Roaster’s Companion by Scott Rao (2014))
When Blending Makes Sense
Blend goals (from Rao and Racineux & Tran):
- Create a unique, consistent flavor profile not available in any single origin
- Maintain consistent flavor throughout the year as seasonal green coffees come and go
- Manage cost by substituting components based on availability and pricing
- Build a named blend identity for marketing
- Create espresso blends that balance acidity, body, and sweetness for milk-based drinks
Single-origin counterargument: Single origins, especially from high-quality producers and specific micro-lots, offer traceability, distinctiveness, and the full expression of terroir, variety, and processing. They command price premiums in the specialty market. (source: El Arte del Café by Racineux & Tran (2017))
Post-Blending (Blend After Roasting)
Rao’s preferred method. Each component is roasted separately to its ideal profile, then the roasted coffees are combined based on taste.
Post-blend procedure
- Set up a Cupping (Cata) of all potential blend components using large samples (e.g., 20g grounds / 320g water)
- Combine liquid from the brewed components into an empty cup in the target ratio (e.g., 3 equal components = 1 spoonful each; 50/25/25 blend = 2 spoonfuls of the first, 1 each of the others)
- Taste the blend; adjust ratios iteratively
- Once the blend is settled, brew it normally to confirm the cupping results
- Document the blend formula with component lot, roast date, and ratio
Advantage: Each component can be roasted to its ideal profile. Allows fine-grained control.
Challenge: Requires separate roast batches; components must be combined after roasting and before packaging.
(source: The Coffee Roaster’s Companion by Scott Rao (2014))
Pre-Blending (Blend Before Roasting)
Green coffees from different origins are combined before roasting and roasted together.
Pre-blend requirements (all must be met for good results)
- Blend the green coffees 2–3 days before roasting to equilibrate their moisture contents
- Use only beans of very similar size and density — different sizes roast at different rates, causing uneven development
- Use only beans of the same processing type (e.g., all washed or all natural) — washed and natural coffees roast very differently
Advantage: Single roast batch; simpler workflow.
Risk: If components have different densities, sizes, or processing types, some beans will be under- or over-developed relative to others in the same batch. Results can be inconsistent across lots. (source: The Coffee Roaster’s Companion by Scott Rao (2014))
Blend Construction Principles
From El Arte del Café:
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Limit blends to 3–4 components maximum — beyond this, individual qualities dilute each other into indistinction
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Start with equal proportions, then adjust: halve the proportion of any dominant component; double any component whose contribution is too subtle
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Example: 50% Brazil / 25% Guatemala / 25% Ethiopia
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Central American coffees (Costa Rica, El Salvador, Guatemala) offer aromatic complexity and acidity — suitable as single origins for filter or as acidity/complexity contributors in espresso blends (source: El Arte del Café by Racineux & Tran (2017))
Consistency Challenges
Rao notes that blending is “inherently challenging” because there are too many moving parts to blend by formula reliably:
- Green coffee quality and flavor vary throughout the year within the same origin
- Roasting consistency varies batch to batch
- Seasonal availability forces component substitutions
He recommends blending by taste rather than strict formula, accepting that results will not be perfectly consistent. (source: The Coffee Roaster’s Companion by Scott Rao (2014))
Relevance to Kaiserblick
Kaiserblick Specialty Coffee produces both single-origin micro-lots and espresso blends (see Roasting Service). Rao’s post-blend approach by taste is directly applicable to Kaiserblick’s espresso blend development. Given that Kaiserblick’s lots are all washed process from the same region (Apaneca-Ilamatepec), pre-blending of similar-density lots is also feasible for espresso blends intended for coffee shop customers.
The European export market (Green Coffee Trading) is primarily focused on single-origin green coffee for quality-conscious roasters. Blending knowledge is most directly relevant to the local roasting and café supply operation.