What is the reason you fill a coffee maker with cold tap water, never with hot? Please help me out here...?

Question

I was brought up always filling a water cooker or coffee maker with cold rather than hot tap water, and that there was a good reason. I was hard pressed to produce that reason recently, other than I think it has to do with damaging the appliance - but is that due to calk or throwing off the regulator? Or is this all just "something Mother always did"? Most people I know take this rule for granted...until now.

Answer 1

hot water makes the pipes corrode, cold water doesn't. hot water often contains minerals that change the taste of coffee and tea

Answer 2

Coffee Maker With Hot Water

Answer 3

Your standard run-of-the-mill coffee maker uses an inline heater and a check valve. The water flows down through the check valve into the inline heater, where it is heated to the flash point. The steam then blows the boiling water up out of the pipe into the coffee basket, emptying the pipe. When the pipe is empty, the cold water in the tank flows by gravity through the check valve and refills the inline heater.

If you put hot water in the tank, the inline heater is much too powerful. It is designed to take a certain amount of time to heat up a load of cold water, but when it encounters hot water it will heat it up in no time and pass the water through to the coffee basket faster than it can filter it.... overflowing basket, water everywhere, and weak coffee.

There will also be a lot of steam and rattling - after discharge the inline heater is still hot, until the cold water cools it off. Then it heats up the cold water until it is hot enough to flash. Imagine, though, what happens when hot water drops onto a hot heater - it flashes immediately and explosively, blowing water and steam out with some violence.

You could certainly design a coffee maker to run on hot water - all you have to do is put a much, much weaker heating element in it. In fact, commercial coffee makers do use a tank of preheated water - when you push the button it just drops the hot water at a measured rate through the basket.

Answer 4

Cool water is poured into the large reservoir & then trickles through a small hole into a lower compartment. Inside the smaller sized lower compartment is a thermostat (switch) & as well a tube that delivers the heated water into the basket. The thermostat acts as a switch when it contracts (in the cooler water). This motion completes an electrical circuit which activates a heating element. The heating element heats the water quickly, & the heated water then rises up through the tube & into the basket. When all the hot water is expelled, gravity causes the remaining cool water in the reservoir to trickle into the lower chamber & the process repeats.
So, therefore; only cool water, not hot, will allow you that wonderful brown liquid!
Thermostat-
An automatic device that regulates temperature in an enclosed area by controlling heating or refrigerating systems. It is commonly connected to one of these systems, turning it on or off in order to maintain a predetermined temperature. Its operating principle is based on the fact that one of its components expands or contracts significantly during a temperature change. This expansion or contraction actuates a control on a furnace, cooling system, or piece of machinery. The thermostat sometimes uses mercury, which expands when heated and rises in a glass tube until, at a predetermined point, it touches an electrical contact to complete a circuit and thereby actuate a control; conversely, during a lowering of temperature the mercury descends in the tube and breaks the circuit. The thermostat often uses a bimetallic strip, which is made of two thin metallic pieces of different composition that are bonded together. As the temperature of the strip changes, the two pieces change length at different rates, forcing the strip to bend. This bending causes the strip to make or break a circuit.

Answer 5

When filling up a coffee maker I always used cold water, when filling up a kettle I use hot water, why you ask? because hot water will throw off a coffee maker's thermostat, and I use hot water in a kettle so that way I wont have to wait as long for it to boil, and once it boils it has reached that temperature where all forms of bacteria have died anyway. so save yourself sometime with the kettle that is. =)

Answer 6

Good question. I always assumed that you don't drink water that comes out of your water heater. Ever drain an old one and all the mineralized stuff comes out of it. So I can see drinking out of the cold water tap. Except I bought this old house and they said the water was off (cold). It wasn't turned off, the pipes were clogged shut. And the clogging stuff was all the mineralized stuff you find in the hot water heater and the hot water pipes were just fine. The guy that helped me repair the pipes said that the cold water pipes always corrode shut but the hot water ones are just fine. So I have no idea. . .but I always use cold water for cooking food and making coffee.
Put a filter on your water and change it often. You will be so surprised just what comes out of your water.

Answer 7

Something Mom always did. The temp. of the water going in will not effect the temp coming out. The only thing it might do is break loose all the crud that is building up inside the water holding area. I use hot water all the time and it keeps the coffee pot much cleaner in the inside.

Answer 8

This is what I have always been told - Cold water is always recommended for this and also for cooking because the water pipes providing the hot water coming into your house , carry certain minerals or deposits that comes off the hot water pipes that can change the taste of your food (or coffee).

Answer 9

Yes, it is something mother always did, but she had a reason for it. The appliance works on a thermostat. When the thermostat gets hot, the coffee maker "knows" it's done, and it turns off. If you started with hot water, the coffee maker would think it was done, even though it hadn't even started yet.

Answer 10

Provided the water is from a kettle or pan and not straight from the hot tap I can't see a problem. Just make sure it is not boiling as coffee should be cooler than boiling. The thing about hot water taps in the UK is that the tank is not enclosed so dust and other nasties could get in.