Experiment Schedule

Scottish Ingredients Through Japanese Craft — Oat Miso

Companion document: Research Programme →

Measurement Conventions

Salt concentration Expressed throughout as a percentage of total mash weight (koji + cooked legumes + water). This is the convention used in food safety literature and allows direct comparison with water activity data. Traditional Japanese practice often expresses salt as a percentage of dry ingredient weight; figures in that convention will be approximately 1.5–2× higher than figures in this schedule.
Temperature Miso maturation temperature refers to conditions after the koji-legume-salt mash is assembled. Koji incubation temperature remains fixed at 28–30°C throughout all stages and is not an experimental variable unless explicitly stated.
Water activity Measure at every sampling point alongside pH. Target aw ≤ 0.85 in finished product. This is the primary food safety metric for miso and should appear in the documentation record for every batch.
Experiment identifiers Each experiment carries a unique identifier corresponding to its stage and sequence: F (Feasibility), O (Oats), S (Scottish expression), P (Process), C (Culinary). Example: O2.4 is the fourth experiment of Stage 2.

Stage 1 — Feasibility

4 experiments

Can oat koji produce a stable, safe and delicious miso?

Fixed variables
  • Grain substrate — Scottish naked oats
  • Legume — Scottish fava beans
  • Salt — Scottish sea salt, 11% of total mash weight
  • Koji-to-legume ratio — 1:1 by dry weight
  • A. oryzae strain — single commercial strain, high-protease profile (specify supplier and catalogue reference before Stage 1 begins)
  • Koji incubation — 28–30°C, standard duration
  • Maturation temperature — 18°C
ID Variable Control Test Purpose Success criteria
F1.1 Baseline fermentation Standard oat koji + fava bean recipe — Establish reference process Stable fermentation, aw ≤ 0.85, no contamination
F1.2 Fermentation timeline Same batch as F1.1 Sampling at months 1, 3, 6, 9, 12 Characterise maturation curve Sensory evolution documented at each point
F1.3 Reproducibility F1.1 Independent replicate batch Confirm process reproducibility Similar pH, aw, flavour profile, appearance
F1.4 Process stability F1.1 Triplicate independent batches Determine batch-to-batch variability Low variance across pH, aw, and sensory
Stage 1 outcome: a validated baseline process and maturation profile. All subsequent stages compare against this reference.

Stage 2 — Understanding Oats

15 experiments

How do oats influence fermentation compared with established miso substrates?

ID Variable Control Test Question
A — Oat Variety
O2.1 Variety type Naked oat Milling oat (conventional husked) Do different Scottish oat cultivars or vintages produce measurably different fermentations?
O2.2 Cultivar Variety A Variety B (two available Scottish cultivars)
O2.3 Harvest year Current harvest Previous harvest
B — Grain Processing
O2.4 Pearling Whole groats Pearled How does grain processing affect enzyme accessibility, hyphal colonisation, and flavour development? Note: toasting experiments should document rancidity indicators at 6- and 12-month sampling points given oats' elevated fat content.
O2.5 Toasting level Untoasted Light toast
O2.6 Toasting level Light toast Medium toast
O2.7 Particle size Whole groats Cracked
O2.8 Particle size Cracked Milled
C — Koji Behaviour
O2.9 Koji substrate Oat koji Barley koji (on same oat-fava mash) How efficiently does A. oryzae colonise Scottish oats, and how does this compare with barley? O2.9 is a key reference experiment: the difference between oat and barley koji on an identical mash isolates the contribution of the koji substrate to fermentation dynamics.
O2.10 Koji spore age Fresh spores Stored/mature spores
O2.11 Koji incubation duration Standard (48 hr) Extended (60 hr)
D — Miso Fermentation Dynamics
O2.12 Maturation temperature 18°C 15°C What maturation temperature and hydration range gives reliable, predictable oat miso fermentation? Note: these experiments investigate post-mash conditions only. Koji incubation temperature remains fixed at 28–30°C throughout.
O2.13 Maturation temperature 18°C 22°C
O2.14 Hydration Standard Standard + 5% moisture
O2.15 Hydration Standard Standard − 5% moisture
Stage 2 outcome: a working understanding of how oat variety, processing, koji colonisation, and maturation conditions influence fermentation. This knowledge determines which settings carry forward into Stage 3.

Stage 3 — Scottish Agricultural Expression

14 experiments

Which Scottish crops produce the richest flavour landscape when fermented using Japanese methods?

ID Variable Control Test Question
A — Legume Comparison
S3.1 Legume species Fava bean Field pea Which Scottish legume produces the most compelling amino acid development and flavour complexity when fermented with oat koji?
S3.2 Legume species Fava bean Yellow split pea
S3.3 Legume species Fava bean Red lentil
S3.4 Legume blend Fava bean 50:50 fava/field pea blend
B — Grain Contribution to Mash
S3.5 Grain addition 100% legume mash Legume + 20% oats How does grain presence in the mash (separate from its role as koji substrate) affect sweetness, texture, and fermentation rate?
S3.6 Grain addition 100% legume mash Legume + 20% barley
S3.7 Grain type Oat addition Barley addition
S3.8 Grain blend Oats Oat/barley blend (50:50)
C — Koji Substrate Comparison
S3.9 Koji substrate Oat koji Barley koji On a standardised legume mash, does koji substrate type produce a measurably different flavour outcome?
S3.10 Koji blend Barley koji Mixed grain koji (50:50)

D — Factorial Interaction Matrix

This is the programme's most analytically powerful experiment. Single-variable experiments cannot detect interactions: the behaviour of barley koji on an oat mash may not be predictable from studying either variable independently. A factorial design captures this.

Oat Koji Barley Koji
Oat Mash S3.11 S3.12
Barley Mash S3.13 S3.14

All four combinations are produced under identical conditions. Results are analysed for interaction effects: does the grain substrate change the relative contribution of koji type? Does the same koji behave differently on oat versus barley mash? This matrix should be treated as the culminating experiment of Stage 3, conducted after individual variable experiments have established baseline understanding of each component.

Stage 3 outcome: a map of Scottish ingredient behaviour across legume, grain, and koji combinations. This determines which ingredient combinations carry forward into Stages 4 and 5.

Stage 4 — Process Optimisation

12 experiments

What parameters produce the most reliable and expressive miso?

ID Variable Setting Expected profile
A — Salt Concentration (% of total mash weight)
P4.1 Salt level 8% Short fermentation, sweet, higher spoilage risk
P4.2 Salt level 10% Light-medium; benchmark for sweet-style miso
P4.3 Salt level — baseline 11% (Stage 1 control) Confirmed reference point
P4.4 Salt level 13% Medium-aged; balanced
P4.5 Salt level 15% Long-aged profile; slower amino acid development
B — Legume Mash Texture
P4.6 Texture Whole cooked beans Maximum texture variation; may affect proteolysis rate
P4.7 Texture Coarse mash Intermediate surface area
P4.8 Texture — baseline Smooth paste (Stage 1 approach) Maximum surface area; reference
C — Miso Maturation Temperature (post-mash assembly)
P4.9 Temperature 12°C Slow, restrained development
P4.10 Temperature 15°C Cool maturation
P4.11 Temperature — baseline 18°C (Stage 1 control) Reference point
P4.12 Temperature 22°C Faster development; higher complexity risk

D — Maturation Duration

Rather than producing separate batches for each duration, a single well-documented batch is sampled across time. This eliminates batch-to-batch variability as a confound and continues the maturation work begun in Stage 1 (F1.2) using the optimised parameters identified in earlier Stage 4 experiments.

Sampling point
3 months
6 months
9 months
12 months
18 months
Stage 4 outcome: confirmed optimal operating parameters for oat miso. This constitutes the technical foundation for Stage 5 product design. Note: commercial A. oryzae starter should not be reused from previous batches; wild strains acquired through backslopping may not maintain the enzyme profile or safety characteristics of the original starter.

Stage 5 — Culinary Design and Product Development

10 experiments · 7 prototypes

How can the knowledge gained be used to create distinctive Scottish misos?

Approach This stage marks the programme's transition from research to design. Every addition must be justified by specific observations from earlier stages — not by culinary intuition alone. The goal is to shape flavour, not to rescue fermentation. Each ingredient addition should be accompanied by a stated hypothesis before the experiment begins.
ID Variable Purpose Hypothesised contribution
C5.1 Scottish dulse Marine umami Glutamic acid reinforcement; mineral complexity
C5.2 Sugar kelp Mineral and oceanic character Contrasting mineral profile to dulse
C5.3 Cold-smoked oats (as koji substrate) Smoke integration Low, integrated smokiness distinct from surface addition
C5.4 Toasted barley addition Malt character Depth and roast complexity
C5.5 Heather flowers Floral aromatics Highland terroir expression
C5.6 Juniper Resinous complexity Woodland and gin-adjacent aromatics
C5.7 Wild garlic Seasonal expression Allium depth; Scottish growing calendar reference
C5.8 Spruce tips Highland aromatics Fresh, resinous, seasonal
C5.9 Whisky cask maturation Oak and spirit influence Vanilla, oak tannin, trace spirit character
C5.10 Peat smoke exposure Controlled smoke character Distinctively Scottish smoke signature

Prototype Products

Prototypes are designed only after the research programme has generated sufficient knowledge to make deliberate, informed decisions. Each prototype is traceable to specific Stage 1–4 findings.

Prototype Core research question Key variables
Pure Oat Miso Can oats stand alone as both koji and mash substrate? Best oat cultivar, optimised processing, confirmed salt level
Oat–Barley Miso Does barley addition increase flavour complexity? Optimal grain ratio from S3.7–S3.8
Fava Bean Miso Maximum umami expression from Scottish legumes Best legume from Stage 3, optimised salt and maturation
Coastal Miso Seaweed integration Dulse or kelp finding from C5.1–C5.2
Highland Miso Botanical terroir expression Heather and juniper findings from C5.5–C5.6
Distiller's Miso Barley-led; whisky cask influence Stage 3 barley mash findings; C5.9
Seasonal Miso Series Ingredient expression through the Scottish growing calendar Wild garlic, spruce, heather at respective harvest peaks

Programme Summary

~55 experiments · 24–36 months
Stage Research question Experiments Timeline
1 — Feasibility Can oat koji produce a safe and delicious miso? 4 Months 1–14
2 — Understanding Oats How do oats influence fermentation? 15 Months 6–20
3 — Scottish Agricultural Expression Which Scottish ingredients produce the richest fermented flavours? 14 Months 12–24
4 — Process Optimisation What parameters optimise oat miso? 12 Months 18–30
5 — Culinary Design and Product Development How do we create distinctive Scottish misos? 10 + 7 Months 24–36
Every experiment isolates a single variable and contributes directly to cumulative understanding. The resulting body of knowledge identifies outstanding combinations and explains why they work — the foundation for a genuinely distinctive Scottish cuisine expressed through Japanese fermentation craft.