Keeping a sourdough starter alive in a Japanese home

A sourdough starter is a living culture, and living things respond to their environment. In Japan, where kitchen temperatures can swing from 10°C in winter to 32°C in summer, a feeding schedule that works in March will not work in August. This is one of the first things Noriko Miyazaki covers in the Pixel Crown workshop, because it is the thing that causes the most home-baker frustration.

Choosing the right flour for your starter ¶

Whole grain flour, whether whole wheat or whole rye, contains more wild yeast and bacteria than white flour because the bran and germ carry most of the microbial life. A starter fed entirely on white flour will work, but it tends to be less and more sensitive to temperature changes. Adding 10 to 20 percent whole rye to each feeding gives the culture more to work with and produces a more active, stable starter.

In Japan, whole rye flour (ライ麦全粒粉) is available at specialty baking suppliers and some larger supermarkets. Hokkaido bread wheat in whole grain form is also a good option and tends to be easier to find. The brand matters less than the freshness: flour that has been sitting in a warm warehouse for six months will have fewer viable wild yeasts than freshly milled grain.

Adjusting for Japanese seasons ¶

In summer, a starter fed at a 1:5:5 ratio (starter to flour to water) at 8:00 in the morning may be fully ripe and beginning to collapse by early afternoon. If you are baking in the evening, this is too fast. You can slow it down by increasing the ratio to 1:10:10, using cooler water, or moving the jar to a cooler spot in the kitchen. Alternatively, keep the starter in the refrigerator and feed it the night before you plan to bake.

In winter, the opposite problem occurs. A starter that peaks in six hours in summer may take 12 to 14 hours in a cold kitchen. Using slightly warmer water (around 30°C) and placing the jar somewhere consistently warm, such as near the rice cooker or on top of the refrigerator, can help maintain a more predictable rhythm.

Signs that something is wrong ¶

A healthy starter smells pleasantly sour, like yogurt or mild vinegar, with a faint yeasty note underneath. If it smells strongly of acetone or nail polish remover, it has been left too long between feedings and the acetic acid has built up. This is not fatal: discard most of it and feed it twice a day for two or three days and it should recover.

Pink or orange streaks in the starter indicate contamination and the culture should be discarded. A layer of grey liquid on top (called hooch) is just alcohol produced by hungry yeast and is harmless: pour it off or stir it in before feeding. A starter that produces hooch regularly is simply being fed too infrequently for the temperature it is kept at.

Levain maintenance is covered in full at the Pixel Crown baking workshop. If you have a specific question about your home starter before then, you are welcome to send a note to hello@pixel-crown.com.