Processing Fresh Chile Peppers
Nancy C. Flores, Extension Food Technology Specialist
College of Agriculture, Consumer and Environmental Science, New Mexico State University.
Many people consider green chile peppers to be a staple in the New Mexican diet, adding flavor and providing an excellent source of fiber, beta carotene (vitamin A) and vitamin C. The most important step in processing green chile is removing the outer skin, which is necessary before further cooking or canning. The skin is not easy to chew or digest and can affect texture and appearance in a dish. Proper chilling and storage will prolong the shelf-life of peppers and one’s enjoyment of this uniquely New Mexican experience.
Choose chile peppers that are mature, heavy, smooth, symmetrical, fresh and crisp. Avoid peppers that are mishapen, shriveled, or have soft spots, bruises with mold or decay.
Application of heat to the surface results in blistering of the skin, which then separates from the chile flesh, making the skin easier to remove. There are several ways to blister pepper skin for easy removal. Fire-roasting, steam injection, microwave heating or any other source of high heat, applied directly to the surface of the pepper, will cause the skin to blister. Roasting slowly over a flame creates carmelization of sugars, which adds a distinct flavor to the final product.
Heat Source Methods for Blistering
Oven or broiler method: Place peppers in a hot oven or broiler set at 400° to 450° F (205° to 232° C) for 6 to 8 minutes; using tongs carefully turn pepper often until skin blisters evenly on all sides.
Range top method: Place peppers on wire mesh over a hot electric or gas burner; using tongs carefully turn peppers frequently, exposing all surfaces to the heat source until skin blisters evenly on all sides.
Outdoor grill method: Place peppers on a charcoal grill about 5 to 6 inches above glowing coals; using tongs carefully turn peppers frequently, exposing all surfaces to the heat source until skin blisters evenly on all sides.
Microwave oven method: Place peppers in a microwave safe dish; cover with secure air-tight lid to allow for steam build up. Place container on rotating plate in the center of the oven, then microwave for 7 to 8 minutes depending the oven wattage and power level (settings may vary depending on microwave oven used). Blistering is not apparent with this method. However, the skin will have a tougher, more brittle texture compared to the raw pepper. Allow steam to fully develop in the covered container for 1to 2 minutes after microwave cooking. Caution: Steam will be released from container when the lid is opened.
Since capsicum can be an irritant to skin and eyes, precautions must be taken to protect eyes with safety glasses and skin with gloves and long-sleeved shirt. Also, it is best to remove contact lenses before this process. To remove residual capsicum oil, slather skin with olive or vegetable oil, wipe with a clean paper towel then wash with soap and water to a full lather. Follow with a complete rinse and dry with a clean paper towel.
Chile skin separation is aided by placing roasted peppers in a microwave safe or heat tolerant covered container or plastic bag (food grade) that will allow for condensate or steam to release slowly from the roasted peppers. Once cooled, the blistered skin will pull off the chile flesh with a gentle tug and an occasional rinse with water. In areas that did not completely blister, the skin can be removed by scraping with a sharp knife or vegetable peeler.
Chilling and Freezing
Freezing packaged roasted peppers in a home freezer has some food safety and quality issues. Roasted peppers must be properly chilled and frozen to ensure a high quality, safe product. Roasted peeled peppers should be refrigerated within 2 hours of exposure to heat. Whole peppers can be frozen unpeeled and are easier to peel after freezing. Roasted peppers must be used or frozen within 3 days of storage in the refrigerator; however, the sooner frozen the better to ensure the best flavor and texture.
Home freezers are inefficient at removing heat quickly from food placed in containers deeper than 2 inches. If storage packages are too large, peppers will freeze slowly, resulting in a mushy texture because of ice crystal formation within the chile tissue. Therefore, it’s best to use shallow containers to allow for quick cooling. Specialized plastic freezer containers with lids or plastic freezer bags are best for storing peppers in the freezer. Remove as much air as possible to reduce the amount of surface crystallization that can form in air spaces during freezer storage.
Another concern is a hot center that, freezing slowly, allows bacteria to grow and become dormant during storage. Once the peppers thaw, the bacteria can revive and cause illness. Ideally, packaged peppers should be completely cooled in an ice bath or refrigerator to less than 40° F before placing in the freezer. Containers or bags should be stacked flat in the freezer allowing for maximum air flow around packages. Peppers can be stored safely in the freezer for up to 12 months.
Commercial Chile Roasting Precautions
Commercial roasters are a convenient and economical way to handle large volumes of chile peppers. Some vendors use garbage bags to hold roasted peppers. However, this practice is dangerous because plastic polymers and chemicals such as pesticides imbedded in the plastic can be released into the peppers when the bag is exposed to heat from the peppers.
Therefore, it is best to use a food-safe container such as a large roasting pan or a pillowcase to collect roasted peppers, then transport to your home in a chilled ice chest. Transfer into smaller containers as soon as possible. Remember to place packaged roasted peppers under refrigeration within 2 hours of exposure to heat.
Figure 1. Flow path for chile roasting.
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Printed and electronically distributed June 2005, Las Cruces, NM.