The Portuguese Alentejo with its wet spring and a rapid rise in temperatures in April is a favorable climate for growing early citrus such as sudachi. The advantage of early fruit is that they are not attacked by the Mediterranean fruit flies, despite a high fructose level. With dry summers there is no need for fungicides. A simple rinse to remove dust is enough. Dry before using the zest.
These Sudachi are grown in a preserved environment, outside the major olive and vine growing areas. So you have a fruit as pure as nature makes it.
Keep the fruit cool between 5 and 8°C in a zip-lock bag. Freeze them for storage for a few months, either whole or prepare grated zest and juice in an ice cube tray.