[Tim Hayward]

Confirmed coffee geeks amongst you will be aware of the legendary modification to a £300 Rancilio 'Miss Silvia' coffee machine that enables it to temp control to within a degree thus bringing it up to spec with machines costing hundreds of pounds more.

Details of how to do the conversion, a fairly elementary bit of screwing together components, are available here, here or at various other places online.

Basically the conversion involves using an industrial control device called a PID which reads the operating temp via a thermocouple and switches the heating on and off accordingly.

The basic thermostats in the Miss Silvia fix temp to within 40 degrees, he PID can do it to within a degree - removing one more variable from the process of pulling the God Shot.

I've been planning to PID my machine for over a year but have been unable to find the kit. Yesterday, however, I located a chap in Sussex with a small company specialising in control kit. He's helpful, friendly and can provide everything I need.

His name's Jez Watson of Paragon Alliance Limited on 0845 - 466 6700

I'll try to post pictures of the project once I get started.

This post has been edited by Tim Hayward: 25 September 2007 - 06:11 AM

[Clerkenwellian]

Thanks - will be very interested to see how this goes!

[bainesy]

Interesting.

I've noticed a few people are ordering cross-Atlantic, taking advantage of the weak dollar, e.g. from this place clickage but I imagine if Jez Watson decided to market specific "kits" (as opposed to the bare components) he could make quite a few sales. I've always been mildly interested in "pidding" my old Gaggia, but not enough so to suffer international delivery and customs charges etc.

Wonder if he is interested in offering that sort of thing?

[Tim Hayward]

I think anyone getting involved with selling any kind of formal 'kit of parts' would run into every problem from health and safety to manufacturers lawsuits.

As far as I know, Jez isn't offering anything that formal. I simply offered his contact details because he's incredibly helpful and managed to talk this particular idiot through the process of specifying parts.

IMHO, he's definitely worth the call.

[slkinsey]

Interesting link, bainesy. Are you aware of anyone else selling PID kits for the Silvia?

[bainesy]

Tim Hayward, on Oct 1 2007, 07:15 AM, said:

I think anyone getting involved with selling any kind of formal 'kit of parts' would run into every problem from health and safety to manufacturers lawsuits.

Is the UK that much more under the H&S cosh than the US?

In addition to Auberins the other place offering the off-the-shelf kits I know of is pidkits. Randy Glass plugs this place, and he also has more than any normal person could ever wish to know about the Silvia at Espresso My Espresso.

Do keep us informed of progress if possible Tim.

[adey73]

Can I trump everyone with this top idiot question.

Even though I only have a rudimentary idea what your talking about. (is it that the heat of water to get the most out of the bean has to be a lot higher than domestic machines provide?).

How do this kit do that and how can I do it too? (forgive me I'm an egullet sheep)

[Peter H]

adey73, on Oct 2 2007, 11:26 AM, said:

Can I trump everyone with this top idiot question.

Even though I only have a rudimentary idea what your talking about. (is it that the heat of water to get the most out of the bean has to be a lot higher than domestic machines provide?).

How do this kit do that and how can I do it too? (forgive me I'm an egullet sheep)

The PID modification reduces temperature variations in the water that comes out of the Silvia. According to one of the links in the original post, the standard thermostat can allow variations in water temperature of up to 20 degrees C, the addition of a PID could be reduce this to 1 degree C.

The result is means more consistent shots and the ability to fine tune the water temp.

[adey73]

but what is the optimum temperature to release the oils from the beans?

Or is that dependant of the variety?

This post has been edited by adey73: 02 October 2007 - 07:47 AM

[slkinsey]

adey73, to answer your question as to temperature: There are certainly temperature differences based on bean variety and/or blend (remember that espresso is always a blend), roast and roasting technique, and brewing method. Going back to your earlier question, it is not the case that good espresso machines have a higher temperature that others can't provide. In fact, the opposite is usually true. Cheap "steam toy" machines that depend on the pressure of steam to force the water through the beans (as opposed to a pump) have to brew at higher temperatures and produce a characteristically "burnt" flavor profile.

What distinguishes the better machines can largely be summed up into two things: First, pressure (how hard can the pump pump). Second, temperature and temperature stability (at what temperature does the machine brew the coffee, and how much variability is there in brewing temperature from shot-to-shot).

By modifying the Silvia with a PID controller, we are attempting to greatly enhance the second characteristic of a better espresso machines: temperature (you can choose your own temperatures with a remarkable degree of accuracy) and temperature stability (the digital readout is handy, but I believe PIDed machines also recover back to the target temperature more rapidly).

[adey73]

So Slkinsey, the Silvia with a PID controller in-particular is the best bit of kit for the cash?

do I set what temperature I want with the digital Pid & it achieves it (like a Pid controlled waterbath)?

And what kind of temp am I wanting for this?

Thanks in advance.

[Peter H]

adey73, the two linked sites above show almost identical temperatures - 109 C and 228 F - this could be a good place to start.

There are several variables that affect the quality of the coffee and the temp is just one of them. Because the PID allows you to control the temperature accurately, it means you can adjust it to consistently get the coffee that you like the best.

I was looking around a while ago for an espresso machine and there was a lot of support for the Silvia in that price range (even without a PID).

[adey73]

Thanks, I read up on the links after I posted yesterday.

[Tim Hayward]

Well, it's bubbling away nicely downstairs :)

Everything arrived most swiftly from the supplier. I picked up a nice black aluminium enclosure with heatsink fins from RS and invested in a box of assorted crimp on connectors from Maplin and set to work.

I measured and made up the various cables first. The two control wires from PID to SSR are heatshrunk together with the thermocouple - this is the umbilical between the Silvia and the PID box. In the short term I've gone with a seperate power cord (I've got plenty of sockets on the bench) and finally a pair of wires with spades at one end and forks at the other to connect the power supply at the brew thermostat to the SSR

Each of these was carefully measured, cut, heatshrunk and I even tinned the ends. Sadly, however, I only had blue and brown wire in my toolkit so they all looked a little similar (those of you with electrical engineering experience, rudimentary intelligence or, quite frankly the brains God gave a cactus might realise what's coming and want to look away about now).

So I gaily hooked it all up and flicked the switch.



Considering I'd just put 240v across the 3v out switching terminals, the 'phut' was reasonably quiet. The destruction however was total.

Jez Watson, laughed happily as I described my utter stupidity and sent a replacement unit by courier. That arrived 15 mins ago which means that, allowing for 12mins and 30s of obsessive checking and rechecking of half a dozen connections, fitting the PID takes two and a half minutes.

Most of the programming is done at the factory so it's simply a matter of setting the brew temperature and running the autotune function. Three keystrokes and you're away.

It's now all running beautifully.

I'd say, as long as you know how to use a crimper, wire strippers, a screwdriver and heatshrink, you should be able to do this.

If you also have some knowledge of electrical circuitry and a little patience you could also save yourself the £114 it costs to replace a burnt out PID.

The other thing I've discovered now I've finished the project is that REAL men, in the coffee world are now fitting two channel PIDs so they can control steaming temp too....


...Bollocks!

[adey73]

Really sounds interesting and I want to do it.
But three questions
1) How does the coffe taste, vaste improvement?
2) Where do you attach the second pid for the steam?
3) Any snaps?

[Tim Hayward]

Does the coffee taste better? Decidedly not.


OTOH I used to be able to pull, on average, about one 'God Shot' in four with all other variables strictly controlled. Fitting the PID means I can invite you round, pull a perfect one for me and follow it with another identical one for you. I can also experiment to improve my shots in .1 of a degree increments


As I understand it, a second channel (rather than a second PID) is used to run a second programme which can control the boiler to a second set temperature during steaming.


Pics? Apologies in advance but here are some...


1. The parts for the umbilical - thermocouple, wires and heatshrink



2. Three cables prepared for installation - Umbilical, SSR-thermostat power, mains supply.



3. Inner gubbins. The blue and brown cables (damn and blast) spade into to the cables which used to serve the left hand thermostat - that's the little round beige puppy with the brass ears. The thermocouple wire is the thin white looking one looping from top-centre round to the right. It terminates in a copper washer which is tucked neatly under the right-hand thermostat mounting screw (just visible under a yellow cable and connecting block. Hey... I never said I was any good at wiring.... or, come to think of it, photography. As the umbilical passes behind the boiler it's protected/held away from it by a small piece of aluminium shim, tucked into the bottom of the central dividing wall.



4. SSR, mounted behind splashplate



5. PID in position and running test. Splashplate hasn't been reinstalled yet.



The PID will be mounted on the left hand side of the casing with ceramic magnets and then, when I'm completely happy that it's running well I'm going to yank off the nameplate and Dremel a sodding great hole in the casing for it, just to piss off the purists.

This post has been edited by Tim Hayward: 09 October 2007 - 11:29 AM

[adey73]

Tim, anymore news on pulling the perfect shot helped by your PID?

[Tim Hayward]

Well so far it's resulted in me forking out for some kind of custom-made tamper - I was getting irregular extraction - then I had to get the stopwatch out again because I realised I wasn't being consistent with time.

Problem is, of course, that three of the bastards a day is enough to cause heart palpitations so I reckon I'm now about a week off of a consitent Godshot

[slkinsey]

Have you thought of a bottomless portafilter?

[Tim Hayward]

Sad, sad man that I am, I think of little else. It's only a matter of time before I have at mine with an angle grinder. Messy but effective.

I think I might try upgrading to a Marzocco basket first though.

[adey73]

Sorry, could you explain to the ignorant what "bottomless portafilter" and "Marzocco basket"?

[Tim Hayward]

I'll try to find some links for this.

Marzocco do a basket - that's the insert to the portafilter that looks like a little tin cup with holes in the bottom - that takes slightly more coffee and has, apparently, 'better' holes.

How one hole can be better than another.... go figure. In the Miss Silvia, though, a big load for a double espresso tends to bind against the bottom of the machine so, in this case bigger does equal better.

The 'bottomless' portafilter is a fashionable new mod wherein the bottom of the portafilter is sliced off so there is nothing between the bottom of the basket and the top of the cup.

This gives the ShotJockey the opportunity to obsessively examine the expressed beverage for the characteristic 'Tiger Stripes' of the perfect shot.

A more cynical mind than my own would, logically, see this as 'finding yet another F-ing stupid thing to worry about'.

I think we'd better just accept that this whole business is getting unhealthy :)

[slkinsey]

Tim Hayward, on Oct 22 2007, 12:58 PM, said:

The 'bottomless' portafilter is a fashionable new mod wherein the bottom of the portafilter is sliced off so there is nothing between the bottom of the basket and the top of the cup.

This gives the ShotJockey the opportunity to obsessively examine the expressed beverage for the characteristic 'Tiger Stripes' of the perfect shot.

A bottomless portafilter also makes it possible to use the La Marzocco triple basket. I'm also told that a bottomless portafilter is a lot easier to keep clean, since you really only need to worry about the filter basket.

A disadvantage of the bottomless portafilter, of course, is that you can't run coffee into two cups at once.

This post has been edited by slkinsey: 22 October 2007 - 10:30 AM

[fisherman]

I'm deliberately not buying a Rancilio, just to avoid getting as obsessed with it as you are Tim, despite the fact I'd love one, I haven't got time in my life to find more things to worry about!

[Tim Hayward]

slkinsey, on Oct 22 2007, 05:29 PM, said:

A bottomless portafilter also makes it possible to use the La Marzocco triple basket. 

Damn you, Sir! This is getting out of hand :)

Quote

I'm also told that a bottomless portafilter is a lot easier to keep clean, since you really only need to worry about the filter basket.

My Mother made a similar decision for me at birth

Quote

A disadvantage of the bottomless portafilter, of course, is that you can't run coffee into two cups at once.

This is my morning Java we're talking about, damnit! The only place it's good to share is Sesame Street

;)

[Gary Marshall]

not fancy a nespresso machine then Tim?

as used by heston and sketch apparently.

[bainesy]

Gary Marshall, on Oct 24 2007, 01:22 AM, said:

not fancy a nespresso machine then Tim? 

as used by heston and sketch apparently.

<...deep breath...> There's a blood-strewn thread brewing somewhere in my mind about the fact that the VERY highest end restaurants fail with coffee. When there are outstanding artisan roasters in Britain, three-star joints still serve Illy, which may not be bad in Trieste, but is not going to be fresh (vacuum-sealed tins notwithstanding) months after roasting. It's not difficult to train your staff to be baristas, and there is a whole world of difference between a good shot pulled from a decent manual machine with good beans, and what is only ever likely to be an average shot pulled from a Nespresso-type auto, with stale beans. In fact, they don't even need an espresso machine: outstanding coffee using good beans and a good grinder with a cafetiere requires almost zero training/effort/outlay.

Anyway - thanks Tim for an entertaining pid installation. Do you know you can buy bottomless portafilters from the excellent Happydonkey for only c. £20? I warn you that since I got mine I've been progressively more dismayed by the poor extraction I achieve.

[adey73]

Oh you're right about shabby restaurant coffee.

There's a two and a half year old Rancilio Miss Silvia on ebay at the moment, I have convinced myself I don't need one yet, http://cgi.ebay.co.u...:MEWA:IT&ih=002
happy bidding

[Tim Hayward]

Just had a most instructive weekend.

I've been producing thin, bitter stuff since installing the PID and farting about around the 102C mark, messing with tamp and pack to no avail.

I started using a spreadsheet to record temps at the thermocouple throughout the pull...

Look. If you're going to laugh, I'm going to get all huffy and walk out :)

As long as the machine had heated for a while (I've had mine on a timer for ages so it wakes up an hour before I do then puts itself to bed, waking only to preheat for a mid morning double and the post lunch livener) temperature at the thermocouple would drop by around 10 degrees during the 22 second pull.

Then I worked out the difference between temperature and heat and started using my laser thermometer (stop bloody sniggering at the back!) to check the temperature at the brew face. Crucially, while the PID read out a drop from 102 to 92 near the heating element, the temp at the coffee surface remained a consistent 97. This, I guess, is the advantage of the brassy mass of the Silvia - it holds heat.

Anyhoo, I leaped on one of the Baristas at Borough Monmouth on Saturday and asked what the temp was at his brew face. He laughed at my geekiness, pointed me out to his friends, raised his eyebrows and made several humiliating asides before gazing straight into my eye and whispering "87, plus or minus 2" - such is the tragic, secretive cameraderie of the truly afflicted.

I immediately dropped my PID temp to 92 and, on first pull, produced the kind of sustained, self-supporting crema that a pornstar would describe as 'Serious Wood' - about 7mm deep, tiger-striped and wouldn't quit after a minute of waiting.

Now I'm messing with pack and tamp but, frankly, it's making much less difference - really just refining.

Up till now, I've been buying my stuff preground from Monmouth for consistency and freezing it in 100g baggies so it looks like I'm going to be asking Santa for Mazzer to further perfect my life.

Why on Earth didn't I start a cheaper habit - like crack

This post has been edited by Tim Hayward: 28 October 2007 - 01:29 PM

[adey73]

Tim, you're changing my mind I might bid on the ebay number!