In order to understand grease , we need to define it. According to Encyclopedia Britannica, grease is defined as a “thick oily substance consisting of inedible lard,the rendered fat of waste animal parts. There are also petroleum and synthetic types of grease,but for cooking purposes,we are dealing with the basic inedible lard-the rendered fat of waste animal products.
Here are some different colors of grease and where they come from:
- White grease - made from inedible hog fat and has a low content of free fattacids.
- Yellow grease - made from darker parts of the hog.
- Brown grease - contains beef, hog and mutton fats.
How does grease get up on the roof? Grease much like water, vaporizes at high cooking temperatures. This vapor rises up from fryers or cooking surfaces and is drawn into the hood system (aka kitchen exhaust system), then thru the ductwork and up towards the rooftop fan which is sucking the vapor out to expell it into the air. If this system was not in place, the kitchen and restaurant would fill up with smoke and be way too hot and the ducts would all eventually become clogged with grease, as would the fan. As the heat and grease vapor rises, it will stick to every surface it comes in contact with. What makes this situation even worse is: once the grease vapor cools down, it resolidifies back into its original form. Depending on volume of cooking, over time, the whole system is covered in grease. The rooftop fan draws this grease out of the system and into the air. Unfortunately, some of this grease lands back down on the roof or the fan is overworked and it starts dripping out of the fan and onto the roof itself.
What happens when grease gets on the roof? The grease, after it is cooked and goes thru the hood system, becomes oxidized. When it hits the roof in combination with the other natural elements, the rooftop grease will start deteriorating the roof.
What is the solution? We have several solutions to this problem. The most apparent one is to increase the cleaning frequency of the system. This solves much of the rooftop grease problem, as the roof should be cleaned free from grease during regular hood cleaning service. Another solution is to install a grease trap on the rooftop fan to catch any excess dripping grease. Another solution is to clean the roof with degreaser on a more frequent basis. A monthly service would be separate from a regular full service cleaning.
What are some of the other problems when dealing with grease?
- Grease is an insect - ants, roaches, etc and rodent attraction. The fact of grease being there-as a food sourse and the smell of the grease, attracts all types of varmints from rats to birds to mice.
- Heavy grease build up will cause the rooftop fan to not work as it should. Grease build up on the fan can bend the fan blades and throw the fan off balance. This would cause the fan to not suck properly as it was intended. This has a chain reaction because if the grease and hot air are not drawn into the hood system, it will throw off the air balance in therestaurant-which means your air conditioning will be working harder to maintain a constant cool temperature—this will cost you more on your electric bill.
- Grease also is a fuel and here is where it becomes dangerous. Think about it. Grease is lined on just about every part of the kitchen exhaust system. Then you have the high temperatures of cooking-which sometimes can throw flames up into the hood and you have a recipe for disaster. National fire code statistics show over 95% of kitchen fires are due in some way to kitchen grease and oil. Annually, over 120,000 restaurant fires are reported each year and the problem usually is the greasy cooking equipment. Kitchen fires from grease cause over 300 million dollars in damage each year in additon to over 3000 injuries and over 200 deaths per year. The average cost to fix up what happened from a grease fire is in the tens of thousands of dollars. Not to mention lost business on top of that. Add in all the aggravation you would have to go thru to get things right and back to normal. How much is the annual cost to service your kitchen exhaust system properly? Not much compared to these costs.