Scottish Ingredients Through Japanese Craft — Oat Miso
Companion document: Experiment Schedule →
| Overview |
This project investigates whether traditional Japanese fermentation techniques can reveal previously unexplored culinary potential within Scottish agricultural ingredients. Rather than reproducing Japanese ingredients in Scotland, the objective is to apply Japanese craft to Scottish raw materials, allowing local terroir to express itself through an established fermentation tradition. The research is founded on the principle that technique may travel while ingredients remain local. The first model system chosen for investigation is miso. Rather than viewing miso as a fixed recipe, this programme treats it as a controlled biological process through which the behaviour of Scottish grains and legumes can be systematically explored. |
| Research question |
Can Scottish oats become a first-class substrate for miso fermentation, and what new flavour landscape emerges when Japanese fermentation is applied to Scottish agriculture?
The outcome is intended to be knowledge rather than recipes. Successful products will emerge from understanding the process rather than from isolated experimentation. |
| 1 — Understand before optimising | Optimisation without understanding produces accidental success. The first objective is therefore to understand how Scottish ingredients behave during fermentation before attempting to create an ideal product. |
| 2 — Change one variable at a time | Every experiment should answer a single question. Only one variable should change within any trial unless a later stage specifically investigates interactions. This ensures that every observation contributes to cumulative understanding. |
| 3 — Measure process as carefully as flavour | Excellent flavour is the consequence of successful fermentation. Every batch should therefore be documented throughout fermentation rather than evaluated only at completion. Sensory evaluation and process measurements carry equal importance. |
| 4 — Let Scotland express itself | Scottish identity should emerge from the agricultural materials themselves rather than through decorative flavour additions. The project therefore prioritises oats, barley, fava beans, peas and Scottish sea salt before considering ingredients such as smoke, heather or botanicals. The intention is to discover what Scotland naturally tastes like when interpreted through Japanese fermentation. |
| Oats as a koji substrate |
Oats present specific challenges that rice and barley do not. Their beta-glucan content (3–7%) creates viscous conditions during steaming that can restrict hyphal penetration and limit oxygen diffusion to the grain interior. Standard rice and barley steaming protocols may underperform. Their fat content (5–9%, compared with barley at approximately 2.3% and rice at approximately 0.5%) introduces a rancidity risk that compounds over 12+ month fermentation windows. High-oleic and linoleic fats are reactive under the warm, humid conditions of long-term miso maturation. Their surface texture — particularly in husked conventional oats — may require different preparation relative to the established barley koji protocol: steaming temperature, moisture level, cooling approach, and incubation air circulation all warrant deliberate attention rather than direct transfer from barley practice. A practical starting point: naked oats (dehusked) may offer more reliable initial colonisation than conventional husked oats, as the lower surface beta-glucan barrier allows earlier hyphal attachment. Steam until just yielding but not collapsing; spread thin; maintain strong air circulation during incubation at 28–30°C. Document all preparation choices explicitly. |
||||||||||||||||||
| Fava beans as protein substrate |
Fava beans are the correct Scottish choice. They are also a genuine departure from the soybean baseline, and it is worth understanding why. Fava beans have lower total protein content (20–30%) than soybeans (36–40%), and their amino acid composition contains less free glutamic acid — the primary precursor of the characteristic umami of miso. They also contain antinutritional factors (vicine, convicine, tannins, phytic acid) that may partially inhibit enzyme activity during early fermentation, affecting the pace of amino acid development. The result is that fava-based miso will develop on a different trajectory to soybean miso regardless of grain substrate. The question is not whether oat-fava miso tastes like Japanese miso. It is whether it is delicious on its own terms and expressive of Scottish agriculture. |
||||||||||||||||||
| Fixed variables for Stage 1 |
The following must be explicitly documented and held constant across Stage 1, rather than left implicit.
|
| Stage 1 — Feasibility |
Can oat koji produce a stable, safe and delicious miso?
This stage establishes whether oats are a viable fermentation substrate. No optimisation is attempted. A single baseline recipe is produced and sampled across maturation. Reproducibility is confirmed through a second independent batch. Variables remain fixed throughout. The batch is sampled at months 1, 3, 6, 9 and 12. The objective is to understand maturation rather than to compare recipes. |
| Stage 2 — Understanding Oats |
How do oats influence fermentation compared with established miso substrates?
Once a working baseline is confirmed, the oat substrate is investigated systematically. One variable changes per experiment. Areas of investigation include oat cultivar and variety, grain processing method (pearling, toasting, particle size), koji behaviour on oats versus barley, miso maturation temperature, and mash hydration. Temperature experiments in this stage investigate miso maturation conditions — after the koji-legume-salt mash is assembled — not koji incubation temperature, which remains fixed at 28–30°C throughout. |
| Stage 3 — Scottish Agricultural Expression |
Which Scottish crops produce the richest flavour landscape when fermented using Japanese methods?
With oat behaviour understood, the agricultural palette expands. Legume species (fava bean, field pea, yellow split pea), grain additions (oats, barley, combinations), and koji substrates are each explored individually. At the close of Stage 3, a factorial interaction matrix crosses mash grain (oat, barley) against koji type (oat koji, barley koji). This is the programme's most statistically powerful experiment, producing combinations that single-variable experiments cannot reveal, and should be treated as the culminating experiment of the stage. |
| Stage 4 — Process Optimisation |
What parameters produce the most reliable and expressive miso?
Only after understanding the system should parameters be optimised. Salt concentration, texture, miso maturation temperature, and maturation duration are each explored with a clearly defined baseline and a full range. No variable should be explored only at its high or low end. |
| Stage 5 — Culinary Design and Product Development |
How can the knowledge gained be used to create distinctive Scottish misos?
Only after approximately 18–24 months of structured research should culinary creativity begin. Scottish ingredients — seaweed, smoke, heather, juniper, wild garlic, whisky cask — are introduced as deliberate design choices justified by observations from earlier stages, not as exploratory variables. Each addition should have a stated hypothesis. Finished product prototypes are designed at this stage, with each prototype traceable to specific findings from the research programme. |
| Protocol |
Every batch is treated as an experiment rather than a recipe. Each receives a unique identifier corresponding to its stage and sequence (e.g. F1.1, O2.4, S3.9). Photographs should be taken under identical lighting conditions at every sampling point. Consistency of documentation is considered as important as consistency of production. |
| Required fields |
Batch parameters
Process parameters
Measurements (at each sampling point)
Sensory and observational
|
| Fermentation Performance |
|
| Sensory Quality |
|
| Expression of Place |
The final criterion asks a different question. Not: Does this taste like Japanese miso? Instead: Does this reveal something previously unrecognised about Scottish ingredients? This criterion cannot be scored numerically. It requires qualitative judgement at the conclusion of each stage. Only products that express both Japanese craftsmanship and Scottish agricultural identity fully satisfy the aims of this programme. |
| Future investigations |
Oat miso is the first case study within a broader research programme exploring Scottish ingredients through Japanese craft. Future investigations may include:
|
| Governing principle | Each project follows the same philosophy: Japanese technique provides the method. Scottish agriculture provides the identity. The ultimate goal is not to imitate Japanese cuisine, but to discover a new Scottish culinary language through the disciplined application of Japanese fermentation craft. |