# Temperature sensor for classic



## SDcoffee (Aug 28, 2014)

Been considering a pid for my classic but found this approach to temperature surfing which I'm planning to try in the meantime:

http://www.home-barista.com/tips/different-approach-to-gaggia-temperature-routine-t22059.html

I've tried to use the same thermometer this guy used but it broke when I tried to take it apart. Has anyone got any suggestions of a digital thermometer to use with a sensor I can attach to the boiler wall? Off to maplins shortly for inspiration!


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## les24preludes (Dec 30, 2017)

Pulling up this thread again because I'm interested too. I've heard of attaching the sensor with teflon plumbers tape for instance, or a cork, or no doubt other means are possible.


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## El carajillo (Mar 16, 2013)

That post is 6 years old, electronics and everything else has moved on considerably (look at machines)

For consistent brew water temperature shot after shot and consistent coffee taste go for the PID.

Having recently fitted a Mr Shades PID I can say the difference is night and day, I can also pull from a 20 gm basket and still get same results.

I also fitted the steam side of the PID (I could steam milk consistently without it) but again this improves the ease and consistency of the steam.

NB You still have to refill the boiler and should not try to steam excessive amounts of milk.


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## les24preludes (Dec 30, 2017)

From what I read the PID doesn't address the drop in temperature during the actual shot itself - not sure if this is true. The Gaggia boiler is small so loses heat with the inrush of cold water. I was speculating about upgrading to a Silvia to get a bigger boiler but frankly I generally just make coffee for myself and generally just use 30-40ml water for a double, usually less. So even a 100ml boiler might be enough for my purposes.


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## ashcroc (Oct 28, 2016)

les24preludes said:


> From what I read the PID doesn't address the drop in temperature during the actual shot itself - not sure if this is true. The Gaggia boiler is small so loses heat with the inrush of cold water. I was speculating about upgrading to a Silvia to get a bigger boiler but frankly I generally just make coffee for myself and generally just use 30-40ml water for a double, usually less. So even a 100ml boiler might be enough for my purposes.


The PID does address the drop in temperature during the shot as it switches the boiler back on much closer to the target temperature than a mechanical thermostat.


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## Mrboots2u (May 10, 2013)

les24preludes said:


> From what I read the PID doesn't address the drop in temperature during the actual shot itself - not sure if this is true. The Gaggia boiler is small so loses heat with the inrush of cold water. I was speculating about upgrading to a Silvia to get a bigger boiler but frankly I generally just make coffee for myself and generally just use 30-40ml water for a double, usually less. So even a 100ml boiler might be enough for my purposes.


Silvia still has a huge deadband for temp despite the bigger boiler as it has a pants temp regulating system

Intra shot it might be better than a classic but its still a guessing game what temp you are starting out at.


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## J_Fo (Dec 24, 2017)

You might as well bite the bullet and get a @MrShades PID

You'll end up getting one sooner or later and when you do you'll just wish it'd been sooner anyway...


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## MrShades (Jul 29, 2009)

Mrboots2u said:


> Silvia still has a huge deadband for temp despite the bigger boiler as it has a pants temp regulating system
> 
> Intra shot it might be better than a classic but its still a guessing game what temp you are starting out at.


I'd add to this and say that the Silvia is a nightmare for temperature control - even with a PID - as the elements are inside the boiler, but the standard thermostats are just bolted to the outside of it - hence there's a massive delay between applying heat and the thermostats reacting. The Classic is MUCH better in this respect - as the elements and thermostats / sensors are in direct metal-metal contact. It does mean that there may be some latency in the water part of the system, but it certainly makes for a boiler that is more stable and much quicker to stabilise. Ideally you want a boiler with temp sensors within a thermowell, effectively suspended within the water mass, or proper waterproof sensor probes designed for boilers - but you don't get that on lower cost machines.


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## les24preludes (Dec 30, 2017)

Just a question about temp surfing with a Classic. I read that the ready light comes on at 95*. I'm assuming you have to start at a slightly higher temp. to compensate for the drop during the shot. Now, presumably you can do this by:

1. Waiting some period after the red light comes on (but how long?)

2. Pressing the steam button for a few seconds. I assume that since the red light is also on that's heating as well?

How do I distinguish between these two operations?

Also read this regarding best start temperature ''Setting the PID to 105C seems to work well - giving me 92C using the polystyrene cup test.''


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