・ Raisins without oil coating: 200g
・ Cold or slightly warm water: 400g
・ Honey: 1tbsp
※ Raisins are often coated with oil. To determine whether they are or not, check the ingredient list on the raisin package. Coated raisins will have oil listed among the ingredients.
≪How to Make≫
（１） Sterilize a jar (with a lid) with boiling water. When the jar has cooled, add the raisins, water, and honey. Mix this combination.
（２） Cover the jar with its lid, leaving it a little loose, and place it in an environment with an air temperature of about 24℃ (75℉) for several days. During this time, use a spoon to mix the solution well to add air and release gas. The solution will be ready in 2-3 days during the summer, but could take up to 6-7 days during the winter, when temperatures might be lower than ideal. When the solution is ready, the surface will be foamy.
* If the yeast solution appears to be slow in developing, add a little bit of honey or apple core (You can leave the skin on if the fruit is organic.)
（３） The solution will be ready to use when you see raisins starting to float on top and detect a sweet-sour, slightly alcoholic smell. The best time to use the solution is when you see foam on top; this indicates the yeast is in a very vigorous condition.
* If you notice fungus growing on the top of the yeast solution (as might be indicated by a white film), just remove it, carefully, with a spoon. The solution is not spoiled and you can continue to use it. On the other hand, if you notice an acrid odor, the solution is spoiled and cannot be used.
In addition to raisins, other types of dried and fresh fruit – like figs, persimmons, apricots, natsu mikan (type of tangerine), and strawberries – can be used to make a natural yeast solution. Dried tropical fruits, like mango, pineapple, and banana, however, cannot be used.
≪Preserving Your Yeast Solution≫
As you use your yeast solution, add water and keep the solution in a refrigerator. It should keep for 1-2 months without use.
Add raisins (bits of apple core are OK, too) and stir in a small amount of honey or brown sugar. Place the lid on loosely and leave it outside the refrigerator until you see foam starting to form on top again. Repeating this as needed will allow you to maintain your yeast solution and continue using it for baking.
The time necessary to reinvigorate a yeast solution depends on the season and room temperature. In winter, 1 day may be necessary before you start to see evidence that the solution is alive. In summer, it might need only 2-3 hours. For spring and fall, you should see your solution perking up in about half a day.
Recipe Developed by:Kaoru Shibata