Is Miso Ultra Processed?
Not Typically Ultra-Processed
No, miso is not ultra-processed. Traditional miso is Level 1 — a naturally fermented food made from soybeans, salt, and koji mold (Aspergillus oryzae), aged for months to years with no additives or industrial shortcuts.
Key Findings
- •Traditional miso is Level 1 — one of the oldest fermented foods, dating back over 1,300 years in Japan
- •The color difference between white, yellow, and red miso comes from fermentation time, not added ingredients
- •Instant miso soup packets are a different product — typically Level 3 with dried additives and preservatives
Why Is Miso Level 1?
Miso production relies on a double fermentation. First, koji mold is cultivated on rice or barley for 2-3 days, producing enzymes (proteases, amylases) that break down proteins and starches. The koji is then mixed with cooked soybeans and salt, packed into vessels, and fermented for 3 months to 3 years depending on the variety. During this extended fermentation, enzymatic reactions produce hundreds of flavor compounds, glutamate (natural umami), and beneficial microorganisms. White (shiro) miso ferments for weeks, while red (aka) miso ferments for over a year. The fermentation time — not any additive — creates the color and flavor differences between varieties.
Miso Processing Level Distribution
How 824 miso products break down by processing level:
Average ingredient count: 19.0 · Average nutrition score: 5.3/10
Miso Brand Comparison
Comparing the least to most processed miso products in our database:
| Product | Brand | Level | Score | Ingredients |
|---|---|---|---|---|
| Mellow Red Miso, Soybean Paste | Cold Mountain | Processing Level: 1 out of 4 - Minimally Processed | 2.0 | 3 |
| Red Miso Paste, Red | Wegmans | Processing Level: 2 out of 4 - Processed | 3.0 | 5 |
| Red Miso Paste, Red | Wegmans | Processing Level: 2 out of 4 - Processed | 3.0 | 5 |
| Red Miso Paste, Red | Wegmans | Processing Level: 2 out of 4 - Processed | 3.0 | 5 |
| Red Miso Paste, Red | Wegmans | Processing Level: 2 out of 4 - Processed | 3.0 | 5 |
| Hikari Miso, White Miso Soybean Paste | Hikari Miso | Processing Level: 2 out of 4 - Processed | 3.0 | 5 |
| Tofu & Green Onion Organic Miso Soup, Tofu & Green Onion | Marukome | Processing Level: 2 out of 4 - Processed | 3.0 | 5 |
| Tofu & Seaweed Organic Miso Soup, Tofu & Seaweed | Marukome | Processing Level: 2 out of 4 - Processed | 3.0 | 5 |
| Hikari Miso, White Miso Soybean Paste | Hikari Miso | Processing Level: 2 out of 4 - Processed | 3.0 | 5 |
| Edward & Sons, Miso-cup, Savory Soup with Seaweed | Edward & Sons | Processing Level: 2 out of 4 - Processed | 4.0 | 8 |
How to Read Miso Labels
- 1
Traditional miso lists: soybeans, rice (or barley), salt, water, koji culture
- 2
Avoid miso with added MSG, alcohol (ethanol preservative), or bleaching agents
- 3
Unpasteurized miso retains live cultures — look for "live" or "unpasteurized" on the label
- 4
Instant miso soup packets with dried toppings and flavor enhancers are Level 3
Frequently Asked Questions
Is miso paste the same as miso soup?
Miso paste (the fermented ingredient) is Level 1. Instant miso soup packets that include dried tofu, seaweed, MSG, and preservatives are Level 3. Miso soup made at home from paste, water, and fresh ingredients remains Level 1-2.
Does miso contain MSG?
Traditional miso naturally produces glutamate through fermentation — the same compound in MSG but formed through biological processes rather than industrial synthesis. Some commercial miso adds manufactured MSG as a separate ingredient. Check the label.
Is white miso less processed than red miso?
No. White (shiro) miso ferments for a shorter period (weeks to months) while red (aka) miso ferments for 1-3 years. Both are Level 1. The longer fermentation in red miso is actually more traditional, not more processed.