There are many cultivars which are lumped together in being called “New Mexico Chile Peppers.” The mildest are Anaheim M, Anaheim TMR 23, NuMex Eclipse, NuMex Sunrise, NuMex Sunset and NuMex R Naky. The hottest ones are Española Improved, Fresno, New Mexico No. 6-4, NuMex Big Jim and Sandia. New Mexico No. 6-4 is the most widely grown one.
The peppers are green, ripening to a deep red by the end of August. They may be sold green or red. The green ones are sold fresh or dried or canned. Most red ones are left on the plants to dry, then harvested for further drying. The red ones are usually sold either dried whole, made into dried chile flakes or powder, or made into garlands of dried chiles to be sold to tourists. The dried chiles are sold under many different brand names.
The peppers are generally classed as “medium hot”, around 5,000 Scoville Units.
In New Mexico, chiles are actually used as a food rather than a flavouring agent or spice. Green ones are usually used with pork; red ones with beef. Green have a slightly fruitier flavour.
Chile peppers were brought up to New Mexico by the Spanish and were growing there by 1601. Since their introduction, a great variety of chiles evolved in New Mexico. The various varieties didn’t always reproduce true to seed: various sizes and strengths would grow. Some were so small they were really of more use as a spice than food. In 1907, the US Department of Agriculture Agricultural Experimental Station in New Mexico began trials to standardize chile varieties. By 1917, working from chiles that belonged to the Pasilla family of peppers, they developed the first chile that would grow with a reliable size and hotness so that farmers would have something consistent to sell. They called this the New Mexico No. 9. This was grown as the standard chile until 1950, when New Mexico No. 6 was released: it was milder, and ready to pick earlier. Being milder, it could be more widely used by American consumers. New Mexico No. 6-4, milder still, was developed in 1957 and is still the most widely grown one today (as of 2004) in New Mexico.
New Mexico chiles were brought to Anaheim, California around 1900, where they have since developed into the milder chile pepper called “Anaheim”.