The mysterious world of refrigeration.
One thing that is certain through years of experience I can safely say, refrigeration whilst it’s a prescribed mechanical science (you would think it would be the same recipe/method/result all the time) Nothing could be further than the truth!
There is no shortage of work for good refrigeration technicians, systems are Always playing up somewhere, somehow for good reasons or sometimes no reasons, there are so many factors that are involved for the reasons why systems fail, both from the manufactures side and customers side.
Aside from ensuring you have your condensers cleaned at least monthly, in some extreme cases this may need to be fortnightly, and you don’t muck around with the thermostat settings on the unit too much there is little else you can do to help the unit work properly OR, is there?
In 90% of cases your refrigerated unit or coolroom will NOT be even in temperature.
Its all about Air Flow, In around the unit and for the exterior of the refrigeration motor.
- If you walk into your coolroom with a laser temperature reader (I’m not a fan of these they are too inaccurate in use) but its quick enough and simple enough to prove the point. Take a reading from each corner of the room, top and bottom (8 in total) plus directly under the fans and slightly to the back of them and then directly opposite the fans on the next available shelf.
What were your findings?
Depending upon on the point of the refrigeration cycle and the recent room usage I bet you found quite large variations of temperatures.
Did you find your Hot Spots?
That’s right, hot or warm spots nearly every room has them often on the same side as the fan location can be high or low. You may find for example this area could sit perhaps around the 5-6 degree mark whereas the rest of the room is 2-3degrees..
When you are sorting out your coolroom, this ‘warm spot’ is where you want to store your Fruit and vegetable for example, not your Oysters or chicken! Sounds too simple and ridiculous to be true, well it is, and I have seen it oh so many times, where the lettuce is almost frozen and the raw chicken isn’t even cold!
Now the Coolroom and Refrigeration mechanic reading this will fume and say ‘that doesn’t happen in my rooms’, great if that’s true, but in the real world it happens in 90% of cases. There can be many factors such as incorrectly sized fans, or condensers icing up which will lead to reduced air flow in the room. Or no coolroom curtain strips at the door which could be letting in too much warm air into a section of the room.
As a Hospitality professional It’s your LEGAL responsibility to get to know your coolroom and its hot spots, it’s not acceptable when your in court explaining why 100 people that had the chicken are all sick because you didn’t know that part of the coolroom wasn’t cold!
We did a recent site survey for a large food importer to set up an www.i-temp.com.au temperature monitoring system. The coolrooms were massive, you could drive forklifts in them! What we found was that we needed to place many sensors in the room to get all the variable temperatures to be able to claim an ‘average temperature’ across the room. These were million dollar facilities and there was very little variance in the room, but there was some.
One of the reasons why the above example had little variance is because the operator had spaced and packed the room correctly.
This part is essential DO NOT OVERLOAD your coolroom and or refrigerator.
Take a walk into your local big supermarket, take a look at the refrigerated deli shelves or meat sections, note how they are loaded. Nice and even, never overloaded or just packed to the rafters in every little space is filled.
Nice neat lines evenly spaced between and from the front, not too much product on top of each other. They are ensuring that there is even airflow around the product the refrigerated air can move and pass through the layers. The difference between stacking and sorting the shelves like this IS the difference between the system being able to hold the foods at correct temperature or not.
IF you were to load all that product higher/deeper and no gaps between I can guarantee it WILL NOT be at correct temperature.
Now your big name supermarket holds/stores/sells MILLIONS of dollars of food in each store, they cannot afford the risk of loosing product due to incorrect storage temperatures, or the risk of food poisoning. Their refrigeration costs are also one of the biggest expenses they have, they cannot afford to have systems working overtime either consuming excess power, in a business with very slim margins it makes a massive difference to their bottom line.
If you have problems with your staff overloading refrigerated cabinets/rooms you could do a lot worse than take them through the supermarket to look and see how they do it.
What about smaller refrigerated cabinets?
The effect can be even worse! Most systems have one fan area usually from the top of the cabinet or just the one side. If the unit is overloaded the far end of the cabinet be it bottom or the far end does not get cold enough, the air just can’t get down that end. Classically I have seen this happen in Ice cream and Gelato shops where they have often a 1 door vertical freezer for all their back up stock. The unit gets packed tight from top to bottom and side to side with tubs of product, packed tight.
Then the customer is complaining that the ice cream in the bottom of the freezer isn’t freezing properly and they are losing product. Its not the freezer it’s the user!
HOW Is the cold air that is blown from the top fan going to get to the bottom if there is no way for it to pass through all the product? Its not going to happen.
Once the freezer stock is reduced and the tubs are evenly spaced out of shelves with gaps between them to allow air to pass the through and circulate through the cabinet the problems is solved, product on the bottom is staying frozen.
Refrigerated Air MUST be able to circulate around the cabinet or room evenly.
Now that we have seen that overloading is a problem, do you know that ‘underloading’ also can be?! What you say, can’t win, overload/underload.If you have a room or a cabinet that is empty the refrigeration system is just working all the time keeping air cool, sounds fine what the problem? Nothing really its just working its backside of wasting power! If you loaded your cabinet room up, lets say 60/70% capacity your refrigeration system will have to work less and save you hundreds and thousands of dollars in power!
How is that so? Thermal Mass the product (take a Coke fridge for example) once cold will keep its own cold in the mass of the product for a certain time frame.
For example, if you turned the coke fridge off, the cans of coke won’t be warm within say 15 minutes they, might go say from 1.5c to 5c but not warm. The thermal mass will take some time for it to warm up. But if that coke fridge was empty and we turned it off it would be a lot warmer in there than the same time, the air warm ups quickly, there is no MASS. The same happens with food products also, the bigger and heavier the slower they warm up as they have more cold mass. Think an icy cold cut of beef say a large top side or blade roast, its going to take some time for that big piece of meat to warm up.
So keep your cabinets and rooms at least 65% loaded your refrigeration systems wont have to work as hard.
Air flow ‘around the system’, and the conditions of that air. This is the other airflow part, the air ‘around the refrigeration motor’ be it a self contained cabinet or a coolroom. How well the air can be pulled in and expelled out of the refrigeration.
In its most simplistic form refrigeration works by extraction of air and changing the state of that air into the next stage. The method is to ‘pull air’ into the system and exchange that air into cold air into the cabinet or room. During this process the excess Hotter air that is pulled from the air that has been taken it is expelled out of the system, leaving just cold air to go into our cabinet/room.
Now the air that is ‘expelled’ during this process has to go somewhere, and it does. You will feel the hot air blowing back off a refrigeration (or Air Conditioning system) it might be off to the side, front.
The key with this air is we need to it to go away! We don’t want the refrigeration system to be sucking this HOT air back into to the system, we want it to suck cooler fresh air. And this is where so many of the breakdowns and problems occur, its known as ‘recirculating’ where the refrigeration system is breathing back in its own hot air and it then struggles to cope as it can’t pull down all this hot air.
Air flow again, you need to work out a way to get rid of this hot air if its being recirculated.
We see the above example often with vertical ref/frz cabinets where the ceiling height is low and the cabinet has a top mounted motor. There is just nowhere for the excess hot air to go and they start to recirculate their own air.
In the above example you could a) install a simple extract fan (like a bathroom fan) into the ceiling on intermittent timer to extract the hot air. Vents in the ceiling and or rear walls can help, but its pretty hopefully to assume the hot air will find a way out.
Having the room fully Air Conditioned (running 24/7) can help in the above example also.
So as well as allowing sufficient clean air for your refrigeration system to breath in, it has to be able to expel the air also. This is a big one.
Here are some other helpful tips below, and some more refrigeration facts and guides can be found here, https://www.airah.org.au/Content_Files/Special-Technical-Groups/Cool-rooms-SME-owners-and-operators.pdf
- Store Meats on the Lowest Shelves
Always store your meat on the lowest shelves of your appliance. Keeping your meat on the low shelves makes clean up easier if you have a spill, but more importantly this practice prevents potentially dangerous cross contamination. If any other food touches any juices or marinade from the meat, you must promptly throw those things away. If you store meat on the higher shelves, they are much more likely to drip down and contaminate the rest of your food, which can ultimately spread harmful bacteria to your customers.
- Leave Space Between Items
The cold air in your commercial fridge and freezer needs to be able to circulate. Although the impulse is to pack things in as well as you can to use every bit of the space efficiently, your fridge needs about three to six inches of space between the walls and the food products to get the best refrigeration. The circulation of air in your fridge prevents hot spots and uneven cooling and freezing.
- Keep Food Off the Fridge Floor
In order to prevent water or other contaminants from seeping into your food, it is important that you store all food off of the floor, including while in the refrigerator. While this is a health code requirement, not every person in your kitchen may be aware of the specific codes that will get your restaurant in trouble. In the heat of a rush of customers, it’s also easy to forget this rule. Having adequate shelving will prevent this problem. Make sure all your staff understands that this rule prevents food contamination and pest infestation in your commercial fridge. A note on the door is often enough to remind them.
- Store Delicate Produce Away From Fans
The fans in a commercial kitchen refrigeration and freezing units are extremely strong in order to encourage circulation, but this air flow can actually damage some of your foods. Berries and fresh greens are vulnerable to damage from these fans. In the freezer, storing food close to the fans increases its potential to get freezer burn. While you may need to fully utilize the space in your freezer, make sure to watch the labels and use the items closest to the fans quickly.
- FIFO; or First In, First Out
Product shelf-life and use-by dates are important for maintaining the quality of your foods. Make sure that you utilize the first-in, first-out (commonly abbreviated as FIFO) principle when organizing your storage units. When stocking, place newer items in the back of your fridge and freezer. If date codes are small, write the dates in bigger numbers on the box before you store it, and be sure to place the items so the dates are apparent. Make it easy for employees to see which products need to be used. Always use open items before opening anything new. This is an efficient method that will end up saving you a lot of money.
- Label Everything
Label the shelves. This may seem unnecessary, but mistakes can happen, so it’s good to have a reminder. Labeling lets someone else who isn’t as familiar with your system come in and find things easily, which can be helpful when you have new hires trying to figure out the kitchen. Labeling your shelves makes it apparent when something is out of place or completely out of stock.
Make sure every employee knows that anything that goes into the fridge has a label. This label should include both the day you made or received the product and the use-by date. It is important that you know when prepared foods, such as chicken broth or puddings, were created. Have a rule about unlabelled food, so no one forgets to label items. Make sure you have pens and stickers for easy labelling so this rule doesn’t waste unnecessary time in your kitchen.
Reasons Why Organization Is Important:
- High quality food is not cheap. Your storage plan maintains the integrity of everything you purchase so that it can be used and doesn’t go to waste.
- You avoid those dreaded health code violations by following organization guidelines. Improperly stored food is one reason your restaurant might be fined or even shut down.
- Utilizing your space effectively increases quality of the food.
- Organization in your commercial kitchen creates a smooth operation. When your staff isn’t wasting time looking around for a specific food in an unorganized refrigerator, they can get back on the line quicker.
- Disorganization in your fridge and freezer makes these units work harder, which means you’ll need to call for repairs more often when your food isn’t cooling appropriately.
- There is less need for cleanup when shelves are organized. Food will have a place and things won’t be thrown in wherever it fits.
- Clean up is easier when shelves are organized.
- Ordering and restocking is easier when everything has a place. You can quickly see items that you need and won’t be looking for more cases in another place.
Organization Pays Off
Do you need more space in your commercial fridge or freezer? Before ordering more units for more space, make sure that the shelves in your current units are organized. Taking the time to do this may be a chore for your staff, and it certainly will take time away from their regular duties, but it will save you money in the long run. If you still need extra help, know that there are plenty of apps for kitchen organization that you should consider using.
Keep track of food waste and track the reasons you are throwing this food away. If it’s quickly going bad in the fridge or freezer, you should invest in better organization for better utilization of product. Don’t let a poorly organized fridge cost you money that should be going elsewhere in your business.
Customize your kitchen to your own individual needs. There are a number of different refrigeration systems that can be installed to keep your food at ideal temperatures before it is cooked and served. Take advantage of different products that work in your commercial kitchen.
Teach your staff the importance of fridge and freezer organization in your kitchen. This is an important foundation to have in your commercial kitchen, so you need to make it a priority. Make sure everyone knows how vital these rules are to your establishment.
If you have a real problem with employees with bad habits, try to influence staff with a reward for doing their work correctly after a week, a month, eight weeks, and so on so that everyone has more reasons to make it a priority in their own performance. You’ll see improvement quicker and create camaraderie within your business when everyone is working toward the same goals.
With so many variables it’s amazing that we can keep food cold at all! And it’s painfully obvious that ‘writing down’ a couple of temperatures per day on piece of paper hardly qualifies as an accurate record of the consistent temperatures of a storage system over the longer 24/7/365 cycle.
The only way you can accurately obtain and prove such data is with digital technology, interdependently and accurately recording data 24/7/365 , go to www.i-temp.com.au to learn more.