# Water temp on extraction



## Dalerst (Jan 22, 2020)

Ive noticed over the last week or so the temperature of my shots has gone down quite a bit to the point where its only luke warm a best, has anyone else experienced this over time and have any pointer to try before i contact sage? Ive even upped the water temperature in the setting which has helped very marginally but not a lot. Machine is a 6 months old barista touch. I know the sage machine rely on pressure/resistance to get the temperature right.

Ive always used bottled water, backflushed every week and a descaled it one since having it. My shots are alway consistent with 18g in 36g out in 30-35 seconds, puck is prepared the same way every time, i run 2 or 3 blank shots just to warm everything before i do my first shot and only ever do 3 shots at a time.

Ive not actually tested the temp coming out the portafilter but I know it should be much hotter, and has been in the past. Just after any ideas, i will descale it again in the morning just incase, but the fact its only ever had bottled water I cant imagine its scaled up at all.


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## Dalerst (Jan 22, 2020)

Ive discovered today that if i speed the extraction up to a 1:3 ratio18g in and 54g out over 25 seconds the shot is a lot hotter than if i slow it down to a 1:2 ratio? Can anybody shed any light why that would be? Being a thermojet system i would of thought the slower the extraction the hotter the shot should be? Or is this just the limitations of sage machines.


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## MediumRoastSteam (Jul 7, 2015)

Is this a simple matter of physics and conservation of energy? The less water you have, the quicker it will cool down as it loses its heat to the cup in order to find equilibrium.

as an experiment, instead of using coffee, use water from the kettle. Which ones cools down faster? 36g or 54g?


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## phario (May 7, 2017)

MediumRoastSteam said:


> as an experiment, instead of using coffee, use water from the kettle. Which ones cools down faster? 36g or 54g?


 Suppose you put two liquids at 100C into an insulated container with two different volumes. The container is open at the top. Fourier's Law tells you the heat flux (flow of heat) leaving the top is initially the same between both, and only depends on the temperature difference between ambient air and the fluid. However, the liquid with the larger volume has more heat energy (which is proportional to volume). The higher volume will take longer to cool, as you say.



Dalerst said:


> Ive discovered today that if i speed the extraction up to a 1:3 ratio18g in and 54g out over 25 seconds the shot is a lot hotter than if i slow it down to a 1:2 ratio? Can anybody shed any light why that would be? Being a thermojet system i would of thought the slower the extraction the hotter the shot should be? Or is this just the limitations of sage machines.


 I've not thought carefully about this, and I'm not sure of the precise answer.

I don't know about the Sage machines, but on the Gaggia single boilers, temperature drop during a 30s shot can be 10C due to the boiler unable to keep up with the fresh water coming in. So it's not necessarily as simple as looking at cooling down of your shot volume. It's also about the fact that on 25s, the boiler does not have to 'hold' the heat constant as long as the 35s shot.

An easy test of @MediumRoastSteam's point about volume losing heat, you can test into an insulated heated container.


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## Dalerst (Jan 22, 2020)

MediumRoastSteam said:


> as an experiment, instead of using coffee, use water from the kettle. Which ones cools down faster? 36g or 54g?


 I will test this tomorrow and see what happens, in principle you are probably correct but im talking about the shot heat as soon as the extraction has stopped. I wouldn't of thought what is just a couple of seconds, would give the smaller 36g time to cool in temperature by that much.



phario said:


> I don't know about the Sage machines, but on the Gaggia single boilers, temperature drop during a 30s shot can be 10C due to the boiler unable to keep up with the fresh water coming in. So it's not necessarily as simple as looking at cooling down of your shot volume. It's also about the fact that on 25s, the boiler does not have to 'hold' the heat constant as long as the 35s shot


 The sage machines run on a thermojet system (instead of a boiler) which is suppose to give instent heat and in theory heats better under pressure as the water remains in the coil longer on a slower extraction. I suppose the only way to test this properly is to see what the temperature readings are during the extraction directly out of the portafilter, at the minute i just dont have a decent probe to do it with.


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## Rob1 (Apr 9, 2015)

Dalerst said:


> Ive discovered today that if i speed the extraction up to a 1:3 ratio18g in and 54g out over 25 seconds the shot is a lot hotter than if i slow it down to a 1:2 ratio? Can anybody shed any light why that would be? Being a thermojet system i would of thought the slower the extraction the hotter the shot should be? Or is this just the limitations of sage machines.


 The brew water loses heat to the coffee. The quicker it passes through the coffee the less heat it loses. 1:3 in 25 seconds is a significantly higher flow rate than a 1:2 in 35 and you'll get a hotter shot as a result (assuming the thermojet system keeps up). The coffee of course still absorbs the same amount of heat but it does so from a larger quantity of water and comes up to temperature faster as it is being exposed to more hotter water at a faster rate than the slower shot.

I don't really know about the Sages but I'd hope the thermojet system only heats water to a certain point and does so at the maximum flow rate the machine can achieve, so slowing the flow down (and the flow through the thermojet) shouldn't make much of a difference because it should be temp controlled....but maybe it isn't? There's also the fact 54g will cool slower than 36g.


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## Dalerst (Jan 22, 2020)

Rob1 said:


> The brew water loses heat to the coffee. The quicker it passes through the coffee the less heat it loses. 1:3 in 25 seconds is a significantly higher flow rate than a 1:2 in 35 and you'll get a hotter shot as a result (assuming the thermojet system keeps up). The coffee of course still absorbs the same amount of heat but it does so from a larger quantity of water and comes up to temperature faster as it is being exposed to more hotter water at a faster rate than the slower shot.
> 
> I don't really know about the Sages but I'd hope the thermojet system only heats water to a certain point and does so at the maximum flow rate the machine can achieve, so slowing the flow down (and the flow through the thermojet) shouldn't make much of a difference because it should be temp controlled....but maybe it isn't? There's also the fact 54g will cool slower than 36g.


 That makes sense, I suppose it a slight floor with the thermojet system.

Thanks for all your help, I will just upgrade it as and when I can afford a new machine.


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## Rob1 (Apr 9, 2015)

Dalerst said:


> That makes sense, I suppose it a slight floor with the thermojet system.
> 
> Thanks for all your help, I will just upgrade it as and when I can afford a new machine.


 What do you mean it's a flaw with the system? What am saying regarding higher flow rates resulting in higher shot temps can be seen in my DB E61. Say the water is 95c when it hits the room temp puck. If it passes through the puck quickly it won't lose much heat. The puck will be supplied with more water at 95c and will heat up faster to temp than if it were supplied with the water at a slower flow rate so it's a double effect: 1. the faster flow rate increases the puck temp quickly so the higher quantity of water is hotter overall as it leaves the puck, 2. the espresso falling into the cup is hotter and collecting at a higher rate so has less time to cool before you get the full yield (which will lose heat at a slower rate compared to a lesser quantity).


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## AJP80 (Feb 29, 2020)

If the shots are significantly cooler than usual (all else being equal) then doesn't it stand to reason that your machine has a problem? If so, then why not speak to Sage to see if they can resolve it?


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## Rob1 (Apr 9, 2015)

Dalerst said:


> That makes sense, I suppose it a slight floor with the thermojet system.
> 
> Thanks for all your help, I will just upgrade it as and when I can afford a new machine.


 OH you were talking about the original issue which is your cooler shots....

Right. What water are you using and have you descaled?


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## Dalerst (Jan 22, 2020)

Rob1 said:


> OH you were talking about the original issue which is your cooler shots....
> 
> Right. What water are you using and have you descaled?


 Ive always used tesco askbeck water in it from new and i descaled it on monday.

Ive seen and read lots of different posts about the thermojet system, many say that you need a slower extraction to give it time to get upto temperature, the fast extraction the less time it has to reach the desired 93c.

I will contact sage just to get their point of view and make sure the machine isnt faulty. Ive only really discovered it in the last few weeks as my inlaws drink espresso and have said there not very hot recently.


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## Rob1 (Apr 9, 2015)

So you didn't notice the temp drop yourself?

A lot of people are used to scalding hot drinks. A trick to use if somebody wants something that will burn their mouths is to preheat the cup to the brim with boiling water.


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## Dalerst (Jan 22, 2020)

Rob1 said:


> So you didn't notice the temp drop yourself


 Ive only noticed since they said. Ive tried one and at best it was warm not hot.


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