Koji ferments are where salt percentages fall apart. A famous cookbook calls garum "about 12% by weight" without saying 12% of what; a shoyu calculator defines strength against salt plus water; the Shockey miso table counts salt against legumes plus koji. Take 1,000 g of meat, 300 g of koji and 200 g of water: "12%" can mean 120 g, 180 g or 204.5 g of salt — and the finished jar lands anywhere from 7.4% to 12.0% actually salted. The fix used everywhere on this site, and in the app, is to say the base every time. The garum & koji calculator shows all three readings side by side, and converts any one of them into any other.
The Shockey presets run salt % of legumes + koji, with the koji ratio setting the sweetness:
| Style | Koji : legumes | Salt % (legumes + koji) | Aging |
|---|---|---|---|
| Sweetest | 3 : 1 | 4.5% | 2–3 weeks |
| Sweet | 3 : 1 | 6% | 2 months |
| Mellow | 2 : 1 | 10% | 6 months |
| Medium | 1 : 1 | 12% | 12 months |
| Salty | 0.5 : 1 | 16% | 24 months |
Worked example: 1,000 g legumes at medium (1:1, 12%) wants 240 g salt — and that lands at 10.7% true final salinity once the salt's own weight joins the mass. The miso scaler runs the whole ladder; the app turns a saved miso into a batch with a tasting reminder at the aging time, which is the part everyone forgets.
The Koji Alchemy preset: koji and water 1:1, salt at 5% of the total. So 500 g koji + 500 g water wants 50 g salt — which is also 10.0% of the koji alone. Two bases, one jar, both true: name them and they stop fighting.
Shoyu's moromi stage is brine math with the strength defined as % w/w of salt + water — the same definition the Fermenterie Keala shoyu calculator uses, with its 12–20% options shown as reference. That's why the salt calculator carries both readings (grams per 100 g water and % w/w of the brine) side by side.
One batch, 1,000 g meat · 300 g koji · 200 g water, salted three honest ways:
| Target | Salt | Final salinity |
|---|---|---|
| 12% of meat only | 120 g | 7.4% |
| 12% of everything but salt | 180 g | 10.7% |
| 12% final salinity | 204.5 g | 12.0% |
Same jar, same "12%" — a 2.9-point swing in the real number. That one table is the entire reason every percentage on this site names its base.
Warm-held garum at 60 °C is a controlled process — hold the whole vessel at temperature and log it like a batch. Ambient garum without the 25–33% traditional salt floor is not a beginner's improv project: the caution in the app quotes the jar's own final salinity so you read the number that matters. Ferments are alive; when in doubt, follow your local food-safety guidance.