Sunday 24 March 2024

Conserving Cooking Fuel

 Conserving cooking fuel

Galley tips,

Keep in mind it doesn't need to be just LPG it could be any cooking fuel.

Liquefied petroleum gas (LPG) is mostly a liquefied gas of propane, however some times it may be a combination of propane and butane.

After cruising extensively in the tropics we found than in addition to conserving cooking fuel, the following tips should also help keep cooking heat out of the boat. While the tips here are geared to galley usage, they can help you conserve energy in any kitchen.

I have thought about arranging the tips in what I believe is an order of impact on your cooking. However we all use our stoves differently and cook a wide variety of foods, and each has their own little idiosyncrasies. The best thing is, most of these tips and tricks don’t cost a thing, and once you have incorporated what works for you into your galley cooking then your likely to not even notice your doing them after a while.

1. Stove Burners. Do your gas stove burners run clean, make sure the flame is colourless or blue. Yellow flames are an indication that incomplete burning is taking place. Before you start addressing the list we found the best thing to start with is to clean the stove burners. We removed the jets and using a jet cleaner removed the carbon build up in the jet. Doing this made the burner more efficient, the flow on effect was that we needing less cook time as it didn’t take as much time to bring what ever we were cooking up to boil.

2. Gas Leaks. Check the regulator, pipes, burner for leaks and also ensure that regulator is switched off after cooking to eliminate any chance of wastage due to small leaks. Check bottle fittings for leaks after any bottle change and regularly check fittings in the supply to ensure there are no small leaks. We keep a spray bottle with dish washing detergent/water mix and spray fittings on a monthly basis. We carry a spare regulator, pipe, pipe nipples and nuts, and importantly the flexible hose that allows the stove to gimbal, just in case repairs need to be done in out of the way places.

3. Cover Pans. Using lids is one of the most efficient ways to conserve fuel. Covering a pan, whether its a frying pan or a sauce pan helps retains far more heat and you can generally cook at a lower setting. Normally we don’t like glass aboard due to the potential for breakage, pan lids are the exception to the rule. With a glass lid, I can see what’s happening in the pan and don’t have to take the lid off to check. Most glass lids are fairly thick treated glass and we haven’t yet had one break even though one or two have made unscheduled flights across the galley.

If you don’t have a lid for a pan you’re using, you can use a plate or even a piece of aluminium foil as a lid. You will need to check your plate is heatproof before you use it on top of the pan, yep plastic or melamine isn't going to work without melting or causing a fire.

For a more permanent solution, buy a stepped universal pan lid. There are a variety of universal pot lids on the market, some employ a stepped rubber ring on the outer lip, the problem here is heat coming around the side of the pot can make the ring very hot or give off bad burning smell. There is glass and rubber or glass and metal combination to chose from, and as products change I cannot really comment of how robust they will be. In some situations it could be a better option to get new pots/pans.

4. Measure Water. Whenever you’re heating water, whether its for tea, coffee or use in a recipe, know how much you’ll need and measure it into the pan or kettle so you don’t waste fuel heating water that isn’t needed.

5. Whistling Kettle. Use a whistling kettle whenever you’re boiling water, that way you will know as soon as it begins to boil and you can turn it off so you won’t waste gas. With out the whistle you almost need to be standing by watching and waiting for it to boil. We also found kettles have different tones and some don't whistle very loud at all, more like a deep hum, so see if you can test it out before purchase, we actually returned one for refund because out side the galley it was not heard.

6. Use a Timer. We have a couple of timers and use them regularly. Electronic timers are cheap, and we buy ours from Ebay not kitchen shops for a better deal. We can also use our phone timer if we need too, so we can carry it where ever we are. We use one timer to set the over all cook time, then when adjusting the flame, set the second timer as a reminder in a few minutes to check the pot is not simmering wildly or not at all. With out a timer (reminder) it’s very easy to forget whats on the stove and let it cook longer than intended, even cooking something one minute longer than it needs, wastes fuel. Simple maths if I only need to boil some thing for 9 minutes and I let it go for 10 then I have wasted 10% of the cook time fuel, do this enough times and it will add up.

7. Plan Ahead. If your food prep has you removing produce from the fridge/freezer and straight into the pot, then your increasing cook time. Cooking time can be reduced by preparing then letting the produce coming to room temperature before its cooked. Another thing to think about is doing all your prep before starting to cook, yep cut it all up and measure it all out, this can save cooking time by not needing to wait for you to prep the next ingredient before going into the pot.

8. Plan Ahead 2. We try and plan our menu by what needs cooking first, however with that in mind we also look at the next days meals and see if the cook time for different meals can be combined. For example, if we are having pasta for dinner and want a pasta salad for lunch the next day, we cook the pasta for both at the one time. Seeing as the pasta to make the salad is going to need to be cold, then cooking it the evening before is a good idea. Even with more pasta the cook time is the same, what does change is of course the time to heat the water initially. If in the morning we are making tea/coffee, oatmeal and perhaps putting yoghurt in the maker we measure out and boil all the water at once to save fuel. As the old Boy Scout saying goes Be Prepared..

9. Use Less Water When Boiling Food. If you’re boiling something such as eggs, pasta or vegetables, you can usually use less water than you think. Most foods cook just as well when they are only barely covered with water as when they are covered by several inches, this is especially true if you keep the lid on during the cook. Every extra bit of water takes just that much more fuel to heat.

Vegetables, breads can easily be steamed in basket in a fraction of the water necessary to boil them in. Steaming is very efficient and can save fuel, water, time, if done right, keep in mind steam is a lot hotter than the boiling water so be careful lifting the lid.

10. Cooking Pasta. Directions for most types of pasta call for cooking in lots of water in an uncovered pan. I can’t tell any difference when I use about half the recommended water and partly cover the pan. Not only does this use less fuel, it also conserves water and significantly reduces the humidity inside the boat.

I have heard through other cruisers that the way they cook pasta is to use half the water called for on the package and salt to taste as you normally would. Here is the instructions: Cover pan and bring to a boil. Add pasta, cover and boil for 3 minutes. Turn heat off and let sit covered for 10 more minutes. Drain or serve straight form the pot if desired.

While I have tried this, with the lid on I cannot stop the pot bubbling up and spilling over once the pasta starts to cook. I have let it boil partly covered for 4 minutes then turn it off and replace the lid fully to let it rest for 10 more minutes, this seems to work for us. However it does depend on the brand, shape or style of pasta, and I have to say some do need a different cook/rest ratio.

11. Turn the Stove Off Before Food is Fully Cooked. Pans and the food in them retain heat and continue to cook for quite a while after you turn a burner off. You can use this heat to finish cooking many items. Rolled oats/Oatmeal as an example, instead of simmering it for 5 minutes, bring it to a boil in a covered pan then turn the burner off, it will be fully cooked ready to serve in 5 minutes. Most other dishes can be turned off 5 to 10 minutes before they’re done, but make sure you keep the pan lid on.

Rice can certainly be cooked using this method. We have been using the absorption method, and found we can certainly reduce cook time. Due to this style of cooking we are not heating so much water, then we turn the flame off after just a few minutes of boil time. I cannot give you a definitive time due to the individual styles of rice or even variations with in various brands of the same rice taking different amounts of time to cook. However most brands/types of rice have an absorption water/ rice measurement on the pack and are usually a good guide, I know that basmati rice uses more water than a plain white rice. This will require experimentation to find the magic number (water and time) when you first start to use this method. We have also found setting the pan up with the measured rice and water an hour or more before cooking can reduce the cook time even more, the only problem we have encountered with pre soaking is sometimes there is almost too much absorption and warming up the rice then isn't easy. Another reason we like the absorption method is due to not needing to rinse the rice after cooking, saving water as well.

Brown rice doesn’t work with this method, however soaking for 24 hours does help slightly. Better still for brown rice when away from civilisation we buy the precooked vac packed brown rice available now. It works a treat and we just warm it up in a pot with a steaming basket (in the bag corner cut off), this way the amount of water is minimal and the steam is super hot making warm up quick and easy.

12. Keep Hot Water in a Vacuum Flask. If you’re boiling water and know you’ll need more in a short while, like when friends who like a cupper or two drop in, boil it all at once and keep the extra in a good vacuum flask. You will have to shop around for a good vacuum flask as the quality varies greatly these days. If you don’t use it all and you need it freshly boiling later, it won’t take nearly as long if it starts out hot from the flask.

13. Oven Tips. Don’t preheat for things that don’t need it, such as most pasta bakes, potato bakes, casseroles. For items that require a preheated oven don’t preheat the oven any longer than you have to, do your prep and try to time it coming to the right temperature as you’re ready to put food in. Keep in mind most baked goods biscuits, muffins, cakes, brownies always need a preheated oven (unless the recipe states otherwise).

If you’re baking in a small dish for part of a meal and there is room in the oven for something else, think about whether a desert a snack or treat could be cooked in the oven at the same time. Or you could throw in a couple of potatoes and make potato salad, or use less fuel as you warm them up for a meal the next day.

Many casserole type dishes or even items wrapped in foil (fish, sweet potatoes etc) or pizza can be cooked in a skillet/frying pan on the stove instead of in the oven. Though this is not always the case as the skillet type does come into play and having a heavy metal lid is certainly better. Cooking on the stove top generally makes more efficient use of the heat. We could make pizza on the stove top and as long as you didn’t know the method most people don't know it didn't come from an oven.

14. Pressure Cooker. Pressure cookers can cut cooking time in half, some times a lot more, and can use less fuel in the process. They are for things that would otherwise simmer for lengthy periods such as stews, corned beef, large portions of meat, soups and tough cuts of meat. Cruisers either love them or hate them, those who love them tend to use them frequently the others rarely if ever. Modern pressure cookers have proven to be safe when used correctly, and are available in a wide variety of sizes from 1-1/2 Litres up to size huge, more than likely too big for the most boat galley’s. If you do go down this route get a good cook book recommending cooking times, as its very easy to over cook different foods. I also know a couple of cruisers who don't have an oven, they use a pressure cooker with out the rubber sealing ring as a stove top oven to bake bread.

15. Thermal Cooking. Stews, soups, large portions of meat and other dishes that require long slow cooking can be slow cooked in a Thermal cooker. For details on the technique, you will need a cook book or adapt slow cooker recipes to suit. You’ll use a lot less fuel and keep a lot of heat out of the boat. We had one and did use it, but not as often as we should have, unfortunately we were not good at getting the anchor up and underway as well as cooking to get the food into the pot early enough during the morning. On those days we did get it together, we could arrive at anchor in the evening and not have too cook just serve up the hot meal. Too easy

16. Size the Burner to Suit Your Pans. Keep the smaller burners for the smaller pans, its amazing how easy it is to forget this simple rule. We have seen and even done it our selves, putting a small pan on the big burner, most of the flame will be just wrapping around the sides of the pan. If the same pan was put onto a smaller burner there would be a lot more bottom surface of pan in contact with the flame, the excess flame will still wrap around the side however there will be a lot less heat lost making for quicker heating and in the process cooking time. Most of the time we only use the big burner for the griddle/fry pan.

17. Prep Small Sized Pieces. Cutting food into smaller sized pieces will reduce cooking time, regardless of the cooking method: baking, boiling or steaming. Don’t cut them too small, until you get used to the quicker cook time or you may end up with a mushy mess. A lot of the time you will need to experiment working out the best size of each component so they all are finished cooking at the same time.

One inch (25mm) cubes are about the smallest you should make pieces if you want various foods – potatoes, meat to still be a reasonable size once cooked, remember the meat will shrink as it cooks. Carrots are fairly robust and 4-6 mm slice will preserve shape. For things like mashed potatoes, you can generally cut the potatoes into ½ (12mm) inch cubes, but watch them so they don’t fall apart.

If you are interested in a pressure cooker, read the cook book for the pressure cooker cook times, the small number of times we used a pressure cooker we learnt vegetable cook time is very very fast and ended up with a soup/mush type constancy on several occasions.

18. Do Dishes in Cold Water. This is if you don’t have an onboard water heater. In Asia we were able to source good solid strong dish soap that didn’t require hot water to clean the dishes. With most good quality liquid detergent you can clean your dishes perfectly in cold water. Greasy items can some times be an exception to the rule however, we have found a little detergent used straight up can cut through the grease. It may take a little more elbow grease to get a baked on mess off, but you can do it. If we use detergent straight we usually rinse in salt and then fresh water rinse.

19. Do Dishes in Hot Water. If you cannot stand the thought of using cold water to wash dishes the best thing is reduce the amount of water you need to heat up. Get a small container that will fit in your sink and wash the dishes in it. In a lot of cases this will reduce the amount of water needed to fill the container rather than the sink, sometimes by half. We also found a solar shower would work exceptionally well to heat water for wash up. However we would need to collect the very hot water into vacuum flasks in the early afternoon because once the sun started to go down the solar bag lost heat really quickly.

20. Use Other Cooking Methods. If you’re really running short on stove fuel, you may be able to stretch it by using an electric equivalent, we have seen portable single plate induction cooker, 12 volt electric kettle or low wattage toasters. (yes, they all need electric power but it may be easier to find diesel than LPG). Also of note are small kerosene burners stoves with a large wick, great care needs to be taken with these but they have been around for years. Of course for emergency what about a stash of hiking stoves with gas cylinder (these cylinders need proper storage however).


I think most hints will work even with an induction cook top, as there is still some residual heat in the cook top surface. The advertising states you can pull a pot off the cook top and place your hand on the area the pot came from. Hello from the real world, not the warped advertising world. Here’s the warning, do not put your hand on the place where the boiling pot/pan came off. I have used this type of stove quite a lot and I can tell you first hand if I did this I would have 3rd degree burns on my hand. If I turned the plate on then removed the pan before it had a chance to heat up there would be no heat on the surface, however once the pan has been heated the ceramic glass top of the stove will come up to the same temperature as the pot that was cooking the food in.

Thursday 21 March 2024

Gas Cylinder Markings

Gas cylinder markings for most US marketed cylinders

WC: The water capacity is how much water the cylinder will hold in pounds. The "WC" stamped on the bottle followed by a number such as "23.8" means the bottle will hold 23.8 pounds of water.

Multiply by 0.42 to convert the water weight to LPG weight  23.8 x 0.42 = 9.996 pounds.  Divide, pounds by 2.2 to convert pounds to kilograms.   9.996 / 2.2 convert to KG = 4.54 KG so a 4.5Kg cylinder

So using the same formular a WC marking of "47.6" converts to a 9.08KG cylinder.  47.6 x 0.42 = 19.992. lb, convert to Kg 19.992 / 2.2 = 9.08 Kg

As a side note , WC is used to measure cylinder capacity because water is not compressible its the best medium to use, whereas LP gas or even air is. Thus WC is a reliable and repeatable measure of capacity. I have read where some people talk about the capacity of the gas can vary due to pressure, in this case there is no room for the variables. 

TW: Tare weight of empty cylinder, in pounds (US cylinders), so if you have a set of scales its possible to weigh the full cylinder and then subtract the TW (Tare Weight) to check if the fill weight is OK. 

DT: Is the length of the dip tube, which is where the bleeder value opening inside of the cylinder is located. This determines how full the tank will get before liquid starts coming out of the bleeder valve, when open. Generally as discussed earlier a WC of 47.6 lbs can be filled with 20 lbs  (9.08 Kg) of LP gas. 

A replacement LPG cylinder valve, the thin tube with the bulb is the dip tube 

Gas cylinder markings for most Australian marketed cylinders

WC: Water Capacity. It is the internal volume at test. This is also the volume of LPG it contains when full. This can be used to work how many kgs of LPG it can hold. In this case due to the markings being in metric, find the "W.C." marking on the bottle, for a 9 kg bottle, the WC is 22.0 Kg. However this is not always the case, this 22.0kg is a generalisation and I have seen a variety of values around this value plus or minus. The normal propane or propane/butane mix at the specified pressure will weigh approximately 41% of the water capacity. Doing the math 41% of 22kg = 9kg  or simply put 22 x .41 = 9.02 

TW: (occasionally TM) is short for Tare Weight, it is the weight of the empty cylinder with no valve. (lets not discuss mass and weight difference)

EW: Is not always there. It is the TW (Tare Weight) plus the valve weight. i.e. the weight of empty cylinder (EW = Empty Weight) before filling, keep in mind the change over of cylinder valve types from POL to LCC27 is under way and could mean the value of the EW of an older cylinder may not be 100% correct but should still be close. 

TP: Is the Test Pressure. You also find the test date and the testers registered number. Usually valid for 10 years.

OK how to work out the number of kgs of LPG is in the cylinder or the cylinder can hold  ? 

A really rough and ready way to calculate capacity. Half the WC and then round down to the closest size cylinder to get the Kg capacity of LPG. So a WC of 22 calculates to 11 Kgs of LPG  the closest size bottle to this is 9 Kg so its more than likely the cylinder you have is 9 Kg  a rough and ready calculation
A better way is get out your phone calculator and multiply the WC value by .41, As an example a WC value of twenty two.  22 x .41 = 9.02 so the cylinder can hold 9 Kg or a WC of eleven, 11 x .41 = 4.5 so a 4.5 Kg capacity cylinder. 

Got a partly used cylinder and want to know how much LPG is left.
The simplest way to check the contents of your cylinder is to weigh it. Weigh the bottle with a set of bathroom scales is normally the easiest, how ever we have found hand held luggage measuring scales work a treat. (doing it on a moving boat underway or at anchor isn't very accurate)

As an example if your partly used 9 Kg bottle weighs in at 11 Kg. 
Take the EW (empty weight) in this case 8.1 Kg away from the of the value of the partly used bottle (11 Kg) as measured by your scales. 
E.g. 11kg – 8.1kg = 3.9kg.   You have 3.9kg of gas remaining from your 9kg capacity cylinder = 43%

This bit will is like throwing a cat amongst the pidgions. I say this because it may take some getting your head around. 
Storing LPG in cylinders allows it to be transported in a smaller physical volume than would be required if the gas was distributed in its natural state. Gas cylinders have internal pressures that are higher than atmospheric pressure. LPG must have a boiling point below 20 degrees Celsius in order to be considered a gas.

When using the actual WC (water capacity) figures stamped into your cylinder to work out your cylinder storage the DT (length of Dip Tube) also plays into the final calculation. The cylinder will usually only be filled 80% of the full volume as there needs to be an area for the gas to form in the cylinder. So any calculations using the WC marking should take into account a full cylinder is 20% less volume. (hence the multiply the WC value by .41)

So doing the calculation a different way, (keep in mind this isnt an exact science due to several variables)
WC = 22      20% of 22 =  4.4        22 - 4.4 = 17.6  so the volume for a fill will be 17.6L.   So the weight of the fill will roughly be 8.979591836734694Kg  I would round this up to 9Kg   

Gas volume can be calculated in litres with some basic mathematics.
For LPG (propane) 1kg = 1.96L. Therefore, 14.2kg = 27.832L
For LPG (butane) 1kg = 1.724L. Therefore, 14.2kg = 24.48L
For a 75:25 butane/propane mix, 1kg = 1.783L.
Unlike water, 1kg of LPG doesn’t equal 1L of LPG. This is because the density of LPG is less than the density of water. In Australia, where LPG is propane, 1kg of LPG has a volume of 1.96L.
Conversely, 1L of LPG weighs 0.51kg.

 If the valve is being replaced trim the dip tube to match valve being replaced, this should then mean the stamped info remains current.

Swap & Go 

As mentioned earlier the filling of cylinders isn't an exact science due to several variables, so to keep legal (weights and measures) the Swap and Go people have reduced the volume of the fill to take account of the fact not all cylinders are created equal and have reduced the amount of gas they fill the cylinders with. This doesn't reduce the cost of course but you know you get a the fill weight they are advertising it is.  

The 9kg gas cylinder is the larger cylinder and is filled with 8.5kg of LPG. The smaller 4kg gas cylinder is filled with 3.7kg of LPG. So what sucks for me is I have a 4.5 Kg cylinder so I always look for a refill station, and unfortunately they are getting fewer every day.