Practical Application to Naturally Smoking Meat

Here is a copy of my latest article written for Nutrispices, Ltd.

PRACTICAL APPLICATION TO NATURALLY SMOKING MEAT

Smoking of meat was originally done for preservation purposes.  Today it serves the purpose of manufacturing a variety of value added meat products.  Smoking at different lengths of time in addition to variations in temperature and humidity aid processors in achieving this.

Smoking and cooking of meats is best accomplished in a series of steps.  First, let us ensure we are familiar with the terms.  We need to keep in mind that modern smokehouses are essentially large ovens with humidity added whether they use gas or electricity as a form of heat.  Some of the terms we deal with are:

Dry Bulb-This is just the actual temperature of the air inside the oven.  Whenever we are talking about the temperature of the air inside the oven we are speaking in terms of Dry Bulb.

Wet Bulb-This is the temperature of the air during evaporative cooling.  It is used to calculate the level of relative humidity.  Wet Bulb is measured using the same type of probe used to measure the Dry Bulb.    A “wet sock”, pictured on the right, (usually made of cotton) surrounds the temperature probe.  The “wet sock” is kept damp by a portion of it submerged in a pan or trough of water.  The Wet Bulb reading will never exceed the Dry Bulb reading. Clean “wet socks” and fresh water are necessary for accurate readings.

Humidity-This is the amount of water vapor expressed as a percentage of saturation.  Percent relative humidity is determined by the relationship between Dry Bulb and Wet Bulb.  Ovens equipped with microprocessors will internally make this conversion.  Otherwise, the conversion can be determined online using the internet.  When the Dry Bulb equals the Wet Bulb, the Relative Humidity is 100%.  Water or moisture is injected into the cooking chamber using either tap water as a source or steam.  Steam is much more efficient; however, the capital outlay is higher.

Dampers-There are two types; intake and exhaust.  A damper is a valve or plate regulating the airflow.  The intake damper when open allows fresh ambient air or smoke (depending on the thermal processing step) into the oven. When the intake damper is closed, this prevents this activity and thus helps seal the oven.  The exhaust damper when open aids in “drawing” the air or smoke through the oven.  When the exhaust damper is closed, it aids in sealing the oven.  The positioning of the dampers is critical and will be listed in the various thermal processing steps.

Air Velocity and Flow-This is important to maintain a consistent smoking and heating environment.  Cold spots or areas of relatively lower temperatures need to be eliminated.  This is more of an issue in larger ovens.

To successfully smoke and cook meat products we need to use the steps as follows.  The parameters such as temperature, humidity and length of time are specific to a product but what is outlined below is excellent for starting points and guidance.

SHOWER Showering for a few minutes to equalize the surface of the product is always helpful.  There may be excess meat particles clinging to the outside of the product; additionally, the surface of the meat will be in various degrees of wetness/dryness depending on the length and conditions of staging or holding prior to the smoking and cooking process.  Dampers open.

CONDITIONING This is a step that is often overlooked, however its importance cannot be overstated.  This is a low temperature, high humidity step for a relatively short period of time.  For example, typical conditioning steps are at 110° F (Dry Bulb) and 80% relative humidity for approximately 30 to 45 minutes.  Dampers closed.

DRYING Drying prepares the surface of the meat for the “acceptance” of smoke.  You do not need a high temperature; approximately 125°F Dry Bulb is suggested.  Many processors will set their smokehouses or ovens at 0% relative humidity.  However, it is best to inject some humidity at this point.  Approximately 20% is a good level.  The reason being that 0% relative humidity is never achieved.  Practicality and experience dictate that 20% is most likely the lowest level achievable and ambient conditions vary from day to day. The drying step is complete when the surface of the product is tacky to the touch.  An improper (too short or too humid) drying cycle will result in a light brown or what is commonly referred to as a muddy color. Dampers open.

SMOKING Always smoke using logs or sawdust from a hardwood.  Examples of hardwoods are hickory, cherry, apple and mesquite.  If these woods are not indigenous to your location any hardwood will do.  Hardwoods result in a darker, richer more robust color.  Smoking is best at a low relative humidity such as 20% and a temperature of approximately 135 °F.  Accomplishing SMOKING in two stages is encouraged.  A second stage of 145 °F and 30-35% relative humidity has been found to be effective.  The length of smoking time is dependent upon what you are trying to achieve in degree of smoke color on the finished product.  Dampers open.

COOKING High temperature and high humidity is needed.  High humidity is extremely important at this step because it results in maximum product yield and minimum cooking time.  Typically, the parameters are 175 °F Dry Bulb at 80% relative humidity.  Higher cooking temperatures achieve a shorter cooking time but usually product yields suffer.  Some processors use what is called a delta cooking temperature.  The Dry Bulb is set at 20 degrees (for example) higher than the product temperature.  So, as the product temperature increases, the dry bulb is increased.  The cooking cycle is complete when the final product temperature is achieved.  Dampers closed.

SHOWER This terminates the cooking process and then initiates product cooling.  Ambient tap water will do; however, some processors add salt to their chilling water to enable a cold-water shower below the normal freezing point of tap water.  The length of time depends upon the diameter of the product.  Research and practical applications have shown that an intermittent shower accomplishes the initial cooling effect in a shorter period than continuous shower.  Dampers open.

Once the temperature of the product begins to decrease due to the shower the product needs to be placed in a refrigerated cooler for proper chilling.

Common mistakes made during the smoking and cooking of meat and practices to avoid are:

·         The use of a “dirty” wet sock. Dirty wet socks result in inaccurate wet bulb readings.  Make sure a clean one is in place at the beginning of each thermal processing cycle.  Disposable wet socks are available. It is well worth the investment of changing the disposable wet sock at the beginning of each cycle.

·         Fresh water not flowing through the pan the wet sock is drawing its moisture from.  Dirty water will cause an inaccurate wet bulb reading.

·         Improper drying of product.  Too short or too high humidity will result in a “muddy” product color.  Too long and the finished product surface will be too dry.  The latter is especially an issue with whole muscle products cooked in nets and sausage products made with natural casings.  Product surface should be tacky or sticky just prior to the drying step

·         High temperature during the cooking step.  There is the temptation to use a high temperature at this point to shorten cooking time.  Product yields will suffer significantly and more than offset whatever may be gained in time.

·         Inaccurate temperature probes.  Periodically verify the probes are accurate to ensure product consistency for food safety and quality reasons.  This can be performed by checking them in ice water to see if the probes reflect the freezing point of water or compare to a standardized thermometer verified for accuracy by an outside laboratory.

·         Not keeping the oven clean.  Dirty ovens lead to black specks on the finished product

·         Too high temperature in the smoke chamber.  Keep in mind, you do not want a fire in the smoke chamber.  The purpose is to produce smoke.  You want the logs or sawdust to smolder.

Using the above as guidance and fine tuning your process using this knowledge will result in a saleable, quality and profitable product.