Post By Andy
Espresso machine hot water tap flow and temperature control?
Is it possible to use the hot water tap of the espresso machines to make filter coffee (pour over)? Doing this would probably require some mechanism to control the temperature and water flow from the tap. Is this possible?
I mean rather than use the hot water tap to pre heat cups and for making long blacks would it be cool to have this additional feature incorporated as well?
I'll reply to your question(s) with a question...
What does the water from your espresso hot water tap taste like?
Pour half a cup and let it cool then taste it.
Do the same with water in your kettle and compare.
Let me know if you can taste the difference blindfolded!
Water from my previous espresso machine didn't taste pleasant from the hot water tap and was of different colour too. So yes there was a difference both is sight and smell before. But my present machine doesn't give me that different taste anymore - at least from my limited experience from this two machines.
I gather you mean that the boiler water from your current machine looks clean and clear and doesnt have any "off" smell.
This is good, because it is the way it should be, while your previous machine seems to have suffered some kind of "suck back" which is common enough in heat exchanger machines that havent been managed properly (the subject of a different discussion).
However, you need to look more closely at the apparently clean water from your current machine. Smell carefully and closely, and taste the water.
Without going into specifics, you will find it actually does have a character that is quite different to water from the same source freshly boilerd in a kettle (why not do a comparison for yourself?).
This is because the water in the boiler is not fresh and oxygenated.....its stale and deoxygenated, sitting in the boiler "long term", and picking up a "hot water system" character.
Would you make filter coffee, tea or use water for cooking, with hot water from the hot water system in your home?
If not, therein lies your answer.
Hope that helps
In regard to the temp from the boiler water, my understanding is that for most heat exchange machines it is pure boiler water forced out by the pressure in the boiler. Ie it's going to be hotter that what you would want for a brew. Some machines (my Faema e98 A1) had a "mixer" adjustment so you could mix in water from tank with the boiler water to get the temp you want.
There is also the potential stale water to take into account as per above. Probably better to just use the water from the group?
With the current design of the espresso machines then it all makes sense now why it's not advisable to use the hot water tap for filter coffee. Perhaps someone can incorporate these to brewing methods in one machine someday - with a different design of course. One that will take into account water quality and temperature stability. Something like a modbar pour over system built-in an espresso machine. Might be very expensive though.
Thanks Andy, TOK, Artman for the information. Very much appreciated.
Happy to let you answer your own question.
Early next year we will be landing the first batch of the 220v/240v Brazen. This is what you want for brew and pour-over as it really is an electronic, very accurate and repeatable hot water heater. There will be a Chemex style glass jug for it too so you can do pour-over with 1 degree accuracy and programmable bloom time with either filter paper or a stainless Kone. It also does a killer job of tea and tisanes with an infuser adapter that I've been playing with.
Coffee Roaster, Home Brew | Incline Village, NV | Brazen
Going through the last of the certification process now for the AU standards and hope to have them here in the first couple of months. Pricing isn't set (bad AU$!!!!) but should be under AU$250 inc GST.
(use the contact us form on the bottom of the forum and we will let you know when they arrive)
If you really wanted a machine that included the ability to supply fresh (oxygenated) hot water at a set temperature, you could in theory take a multi-group HX machine, delete one group head and replumb the unused heat exchanger for that head to supply hot water to a suitable outlet, and incorporate an adjustable cold water mixer solenoid. Given that both cold and hot water volumes would then be able to be measured with flowmeters by adding one to ther cold mixer line (normally hot water can't be measured that way since flowmeters can't handle hot water without the plastic rotor melting) you could, with suitable electronic control to cope with 2 flowmeter signals for one dose, have precise automatic hot water dosage. Most machines don't have this - if the hot water dosage is programmable, it is generally a timed dose, which varies a fair bit due to boiler pressure variations.
If you wanted to get super sophisticated, you could use a variable solenoid steam valve from a La Marzocco Strada EP for the mixer solenoid. Strada EPs have a steam lever that operates a potentiometer, then the electronics pulse the solenoid appropriately to provide the correct steam pressure. Fit a temperature probe to the hot water line just before the outlet spout connected to a PID controlling the Strada EP solenoid, and you could have a fresh, accurately temperature controlled precise dose of hot water at the push of a button.
(Obviously, this would cost more than $250 in parts and a lot of fiddling about to build, but given that there are new commercial coffee machines out there for sale with side panels made of recycled coffee beans, and given the current appetite for customising machines just to be different to the cafe down the road, someone would probably be in the market for such a thing)
Why not just use a thermoblock to flash heat the fresh water?
Partly with the water quality issue but I was after the technical aspect of making the hot water tap function as a pour over source of water. Something like a flexible hose rather than a stiff tube with good quality water and appropriate temperature. Heck you can even set your desired temperature for that tap alone. Just thinking out loud here.
Re: Brazen Plus
I think that's a great device and its a good thing that it's coming to Australia with the appropriate voltage. I would be interested in that - while waiting for the "Espresso machine PLUS" to come out.
Originally Posted by Andy