Quick answer: Fermented rice water is rice water left at room temperature for 24 to 48 hours until slightly sour. Fermentation lowers its pH closer to your hair's and makes its nutrients more available, so most people find it more effective than plain. Dilute it before use, once or twice a week.
Here's a thing most rice water guides gloss over: the fermented version usually works better than plain. It's also the version that nearly made me give up on the whole thing. Fermenting rice was tedious for my busy schedule, and the smell was, well, a lot. But the results were worth understanding, so let me explain what fermentation actually does, how to make it properly, and how to use it without wrecking your hair.
What is fermented rice water?
Fermented rice water is simply rice water that's been left to sit at room temperature for a day or two before you use it. In that time, natural fermentation begins, the liquid turns slightly sour-smelling and its pH drops. That pH change is the whole point.
Why fermented rice water works better than plain
Two reasons. First, fermentation lowers the pH of the rice water so it sits closer to the natural pH of your hair and scalp, which helps the cuticle lay flat for more shine and less frizz. Second, fermentation is thought to increase the antioxidants and make the nutrients, the amino acids, inositol, niacinamide, and vitamins B and E, more available to your strands. Most people who compare the two find fermented noticeably more effective.
| Plain rice water | Fermented rice water | |
|---|---|---|
| Prep | 30-minute soak | 30-min soak + 24 to 48 hr ferment |
| pH | Near neutral | Lower, closer to hair |
| Effectiveness | Good | Most people find it better |
| Smell | Mild | Sour |
| Dilute before use? | No | Yes |
How to make fermented rice water, step by step
- Make a batch of plain rice water first. (Our guide to making rice water walks through the soak and boil methods.)
- Pour the strained rice water into a clean jar and cover it loosely.
- Leave it at room temperature for 24 to 48 hours, until it smells slightly sour. In a warm kitchen it ferments faster; in a cool one, slower.
- Once it smells tangy, move it to the fridge to stop the fermentation.
- Before using, dilute it with an equal part of plain water, fermented rice water is potent.
How to use fermented rice water on your hair
After shampooing, pour or spray the diluted rice water over your hair and scalp, massage for a couple of minutes, leave it on for 5 to 20 minutes, then rinse thoroughly and follow with conditioner. Use it once or twice a week, no more. Because it's protein-rich, overusing it leads to "protein overload," which leaves hair stiff and brittle instead of soft.
The honest downsides
This is the part I lived. Fermented rice water smells sour. The timing is finicky, too little and you've just made plain rice water, too long and it turns sharply acidic and can leave hair stiff. And it ties you to a two- to three-day cycle of making, fermenting, and using it before it spoils. Worth it for some people. For my schedule, it wasn't, and that's exactly why Oriza exists.
The easy way to get fermented-rice-water benefits
After two years of developing the perfect solution, I made a way to get the benefits of rice water in a simple, convenient form, without the smell, the guesswork, or the wait. Our Rice Water Shampoo and Conditioner are infused with rice water and made in small batches in the USA, so it's part of a normal shower, not a weekend project. The Ritual Set adds our Halo Oil to seal in shine.
Want the full picture? See our complete guide to rice water for hair.
— Betsy & the Oriza Team
Frequently asked questions
How long should I ferment rice water?
24 to 48 hours at room temperature, until it smells slightly sour. Warmer rooms ferment faster. Then refrigerate to stop it.
How do I know fermented rice water has gone bad?
A slightly sour smell is normal and means it's ready. A sharply foul or moldy smell means it's over-fermented or spoiled, make a fresh batch.
Do I need to dilute fermented rice water?
Yes. It's potent and acidic, so dilute it with an equal part of plain water before applying.
Is fermented rice water better than plain for hair?
Most people find it more effective, because its lower pH sits closer to your hair's and its nutrients are more available. The tradeoff is the smell and the wait.