Tomatillos, often referred to as Mexican husk tomatoes, are a distinctive fruit fundamental to Mexican cuisine, particularly in the preparation of salsa verde. While they belong to the nightshade family, like tomatoes, the process for determining their peak flavor is unique. Unlike tomatoes, which ripen by color, the tomatillo’s maturity is hidden inside a protective, papery covering known as the husk. Understanding the specific changes to this husk is the most accurate way to know when the fruit has developed its characteristic tangy flavor.
The Critical Indicator: Tomatillo Husk Changes
The most reliable sign that a tomatillo has reached maturity is the transformation of its enclosing husk. When young, the husk is green, plump, and feels loose around the small fruit inside. As the fruit grows, it expands, putting pressure on the protective layer until it completely fills the space. This expansion causes the husk to transition from a soft, leafy green to a dry, brittle texture, often turning light tan or straw-like brown.
The physical pressure from the fully developed fruit typically causes the husk to split, tear, or burst open, usually at the bottom tip. This splitting signals that the fruit has achieved its maximum size and is ready for harvest. In some cases, the once-opaque husk may become translucent, allowing the fruit’s color to be faintly seen.
Visual and Physical Signs of Ripe Fruit
After the husk has split, the characteristics of the fruit itself confirm its ripeness. The fruit should feel firm and solid, having fully expanded to be taut against the enclosing husk. The skin of a ripe tomatillo must be smooth and unblemished. Wrinkling or softness indicates overripeness or dehydration.
The color of the fruit varies significantly by cultivar; many common varieties ripen to a bright green. Specialty varieties, however, mature into shades of yellow, purple, or reddish-purple. Green varieties must be harvested before they turn yellow or deep purple, as this signals the fruit is past its peak and has lost its desirable tangy bite. Ripe fruit also features a slightly tacky or waxy coating apparent once the husk is peeled away.
Harvesting and Handling Ripe Tomatillos
Once the husk has dried and begun to split, the tomatillo is ready for harvest. Ripe tomatillos should come off the stem easily with a gentle twist or a light snip using garden shears. Since tomatillos are non-climacteric, they stop developing their flavor profile once separated from the vine, so they must be picked at full maturity.
After harvesting, the sticky residue on the fruit must be washed off thoroughly before consumption. This natural, slightly sticky layer is a protective secretion easily removed with a quick rinse under running water. For short-term storage, leave the husks intact and place the fruit in a paper bag. Stored in a cool, well-ventilated location, such as the refrigerator’s crisper drawer, fresh tomatillos maintain quality for one to three weeks.