It’s common to notice that organic unpasteurised miso can change in colour over time, and this is often mistaken as a quality issue. In reality, this is a natural characteristic of unpasteurised miso. Because it is a living, fermented food, it has not been heat-treated, meaning the beneficial cultures remain active and continue the fermentation process even after packaging. As a result, the miso may gradually darken from a light cream or orange tone to a deeper brown.
This variation is influenced by factors such as fermentation time, storage temperature, and exposure to air. For example, a freshly produced white miso may appear lighter, while the same batch can deepen in colour as it matures. This is similar to how other naturally fermented foods evolve over time, and it often brings a richer, more developed flavour.
Importantly, a change in colour does not indicate that the product is spoiled. As long as the miso has been stored correctly and there are no signs of spoilage, such as an unpleasant rancid smell or unusual mould, it remains safe to consume. This natural darkening is simply part of the ongoing fermentation process and reflects the authenticity of a traditionally made product.
At Honest to Goodness, we carefully select certified organic miso from trusted third-party producers who use traditional fermentation methods without pasteurisation. These suppliers prioritise quality and authenticity, ensuring the miso retains its natural integrity and beneficial cultures. Each product is sourced with care, so you can be confident you’re receiving a genuine, naturally fermented miso.