Dry Aging

One of my favorite things to eat is a dry aged rib eye, simply pan seared with salt and pepper.  The nutty and intense meaty flavor is the essence of a great steak.  The chemical reactions that happen during dry aging take an ordinary piece of meat to extraordinary. 

So, why is dry aging so special and what does it do to meats?  Basically, dry aging does 2 things.  First it concentrates the flavors of meats giving them an intense nutty flavor and aroma.  Second, it makes meats more tender.  This is a simple explanation, but to understand this technique it's useful to understand the science of dry aging.

Dry aging is a process where meats are allowed to age in a temperature and humidity controlled environment for long periods of time, sometimes up to 40 days or more.  As meat ages, enzymes start to multiply and eat the dead cells around them.  As the enzymes go to work, they break down large flavor molecules into smaller flavorful fragments.  The proteins are broken into savory amino compounds, the glycogen into glucose, and fats are converted to aromatic fatty acids.  These processes are what gives dry aged meats their intense, nutty flavor and aromas. 

Enzymes called cathepsins are responsible for making meats tender.  These enzymes break down the connective tissue between muscle fibers weakening the collagen.  This process not only weakens the structure of muscle fibers, but it also allows for more of the collagen to become gelatin during cooking.  And gelatin adds richness, moisture and mouth feel to meats.  The weakened muscle fibers exert less pressure as they cook, which reduces moisture loss during cooking and carving.

Dry aging is a very simple process, but without the right environment meats can end up turning rancid, instead of aging.  Dry aging is best accomplished in a refrigerator at 34 to 38 degrees Fahrenheit and at about 80% humidity.  Proper temperature controls bacteria growth and high humidity slows the loss of moisture, allowing for the flavors in meat to concentrate slowly. 

How to dry age at home:  Dry aging meats at home can be very difficult without proper equipment.  It takes practice to create the perfect environment.  For the adventurous home chef here are some pointers for dry aging at home:

1. Dedicate a refrigerator just for dry aging.  Refrigerators used for storage of other foods contain too many microbes and bacteria that will spoil the meat.  The meat will also take on flavors from other foods in the refrigerator.  Once you have a dedicated cooler, thoroughly clean it and sanitize it with a mild bleach/water solution.
2. Get a thermometer and hygrometer for humidity.  There are many devices on the market that do both.  Place a pan of room temperature water in the bottom of the refrigerator.  Even at cooler temperatures the water will still evaporate and create humidity. 
3. Line the refrigerator with cedar.  Cedar absorbs smells and will help keep the meat from taking on off flavors.  Cedar is also antiseptic, which is why it was used by the Egyptians for embalming.  So it seems fitting to use it for aging meats.
4. Start with smaller pieces of meat, such as a 4 bone prime rib.  Smaller cuts require less time and are less likely to spoil.
5. Rinse the meat with cold running water before aging.  This will wash away much of the bacteria and other microbes that will cause meat to spoil.  Dry the meat before aging.  Do not wrap or cover meats to be dry aged.  This can cause them to spoil.
6. Age meats until they are leathery on the outside.  The color will become deep red and the aroma will become nutty.  Some spots of the meat being aged may mold or turn rancid.  This is normal. 
7. Before cooking dry aged meats, the outside must be trimmed down to the bright red meat.  All rancid spots and mold should be trimmed.  Cook trimmed meats immediately.

These of course are just general guidelines to get you started.  I would highly recommend that you read up on the subject of dry aging before attempting it at home for the first time. 

For more on dry aging, butchery techniques and charcuterie I am teaching a class called "The Butcher Block" on Saturday, December 10 at 11:00 AM.  This part demonstration, part participation class will cover the basics of dry aging, curing, smoking, sausage making and basic butchery techniques. Join me to learn more...