Temperature Surfing the New Rancilio Silvia 100C Thermostat

[whereshaldo]

I'm hoping to start some conversation about temp surfing the newer Silvia's with the 100C thermostat. Most of the material on Silvia deals with the older Silvias that have the 110C thermostat. I'm not sure why they switched to the lower temp thermostat but the traditional temp surfing methods don't seem to completely apply.

Here's what I do: let it warm up as long as possible. Ideally 1 hour, but often its only about 20 minutes and I flush hot water through the PF twice during that time. Then right before brewing, I flick on the steam switch for 5 seconds, then switch it off and brew.

Are you doing something different or nothing at all? PID-ed Silvia's are on their own unless you have a used PID kit you want to sell me.

Hal

PS, I noticed that the screw on the grouphead is now (was it always) an 8mm hex screw with a wide flat-head slot. The screw was in tight but an 8mm box end wrench loosened it no problem

[erics]

Actually, most of the information on this site (and others) pertains to Silvias with the 100 C thermostat (when not PID'ed). The change from 110 C to 100 C was made very early in Silvia's popularity, e.g. my Silvia is September 1999 production and was certainly originally equipped with the 110 C thermostat. About a year later I changed over to the 100 C t-stat.

From a temperature standpoint, here would be a place (emphasis on "a") to start:

http://www.home-barista.com/forum...out-pid-t4691.html

[Psyd]

Actually, most of the information on this site (and others) pertains to Silvias with the 100 C thermostat

Ehm, most of the stuff that I've heard about temp surfing the Silvia has been based on the 110C t-stat. Waiting any amount of time greater than a minute after the light has gone off with a 100C t-stat would make the temp a bit too cold (I'm thinking, I just switched to the 100C stat myself) and surfing from the time it goes on would be getting it before it reached 100C, wunnit?
I'm curious, too.
I'd suggest that any suggestions, instructions,and experiences with a Silvia be annotated which t-stat she's boasting.

[whereshaldo]

[Edit] The above link mentions that the new thermostat came onto the scene in 2001, much earlier than I thought.

[My understanding was that the newer thermostat didn't come on the scene until Silvia v. 2 (the POD adaptable version?) Maybe I'm completely wrong here, I'll try to find the reference.]

Hal

[Randy G.]

[Edit] The above link mentions that the new thermostat came onto the scene in 2001, much earlier than I thought.
[My understanding was that the newer thermostat didn't come on the scene until Silvia v. 2 (the POD adaptable version?) Maybe I'm completely wrong here, I'll try to find the reference.]
Hal

The earliest that the 100C t-stat came along was mid to late 2001. It definitely came before the model upgrade of "v.2." My Silvia from late 2000 (which was one of the earliest ones with the welded-in heating element instead of the bolt-in heating element) originally had the 110, and when that part died (about mid-2003 I think) all that was available for replacement was the 100C.

[Randii]

Actually, most of the information on this site (and others) pertains to Silvias with the 100 C thermostat

I don't agree with this statement. When I got my Silvia, it was the one with the 100C t-stat, and every time I tried *any* of the traditional temperature surfing techniques with it, they did not work at all. The older temperature surfing techniques - some which tell you to take the shot at 2 minutes - are WAY too cold for the 100C t-stat. Those techniques were developed on the 110C t-stat and do not apply to the 100C t-stat.

I eventually found a post from Jim Schulman, who said that you need to pull the shot just when the light goes out, because the machine is up to brew temp then. I found that the temperature was more stable (and around the same temp) at 1 minute after the light went out. When I pulled the shot, I also hit the steam switch at the same time to further stabilize the shot temperature.

I agree that somewhere there needs to be a listing of the different Silvia temperature surfing techniques for the different thermostats, so people will know which techniques apply to their machine. Lots of people don't even know that there are different thermostats in the machines.

[whereshaldo]

I eventually found a post from Jim Schulman, who said that you need to pull the shot just when the light goes out, because the machine is up to brew temp then. I found that the temperature was more stable (and around the same temp) at 1 minute after the light went out. When I pulled the shot, I also hit the steam switch at the same time to further stabilize the shot temperature.

Just to clarify, 60 seconds after the light goes out you hit the brew switch and the steam switch simultaneously?

It is going to be difficult for me to be this coordinated before I have any coffee.

Hal

[ChrisC]

Just to clarify, 60 seconds after the light goes out you hit the brew switch and the steam switch simultaneously?

I have a new v2 Silvia, obviously with the 100C t-stat, and prior to getting my PID, I waited two minutes after the light went out, then hit the brew switch and immediately afterwards the steam switch (don't worry, it's not that hard, and it becomes habit pretty quick). I based the two minute wait on a recommendation in a post of Dan's where he did temp measurements and found they hit 200F at the grouphead pretty reliably at that point -- but I must confess I don't know what version of the thermostat the Silvia had when he did those tests. And the idea of turning on the steam switch at the same time came from Mark Prince's 'Cheating Miss Silvia' page, but I also confess that at the time I thought it was just so you didn't have to wait so long to start steaming the milk after. It was only later that I realized that it might help temp stability within the shot.

Did I get good results? Tough to say -- I was brand new to coffee at the time, and of course, Silvia is a harsh task mistress. Certainly I would say that at least some of my coffees were very good. I had at least one memorable straight shot that was approaching what I would call godliness.

The catch 22 in trying to figure this out is that all the Silvia owners that have access to good temp measuring equipment have likely already PIDed their Silvias... You could try the styrofoam cup / thermometer test, I guess. And ultimately even if someone here told you what timing they use on your Silvia, the differences with your machine (and grinder, and coffee blend/roast/age, and barista technique, and altitude, etc.) are going to make that a little moot. As annoying as this advice may be, your best option may be just a lot of experimentation to figure out what tastes best to you. It's been 4 months now since I got my PID, and I finally was able to dial in on the perfect temp setting for a type of coffee I've struggled with. While that was a long time, the sense of accomplishment I feel is immense.

(BTW, I do still switch the steam switch on at the same time as the brew switch with my PID, of course -- now I'm just trying to remember to turn it off afterwards every time if I'm not immediately moving on to steaming. )

[Psyd]

I based the two minute wait on a recommendation in a post of Dan's where he did temp measurements and found they hit 200F at the grouphead pretty reliably at that point -- but I must confess I don't know what version of the thermostat the Silvia had when he did those tests. And the idea of turning on the steam switch at the same time came from Mark Prince's 'Cheating Miss Silvia' page,

It may just be me, but if the t-stat turns off the heating element just as the boiler approaches 100C, I'm guessing (with some lee-way for drift) that it isn't getting much hotter than that. With room temp water being pushed in by the pump, and the rest of the metal contact starting to cool the water, I'd say that you're approaching the high end of decent brew temps (96C) fairly rapidly, and it'll start to cool from there. Any waiting would bring that down. I could be wrong, but I have noticed that my near-perfect, clockwork-like reproductions of my daily espressos at my GF's house (where Silvia gets her workouts) have been somewhat less spectacular since I replaced the 110C stat. I've been pulling just as the light goes out, but I'm thinking about trying to get a bit more heat into her before I start.
I'd really like it if the publishers of past and future surf techniques were to label which stat they're surfing.

[ChrisC]

My understanding is that the water gets hottest about 1 minute after the thermostat cuts the power to the heater. This is because there is residual heat in the element that continues to pass into the water during that time. (Maybe you could try brewing at this time for a little extra heat, Psyd?) Then it falls after. Seeing as 200F (a good average start temp for espresso) is 93C, and the heater is turned off when the water is 100C and then the water gets hotter than that for a minute, you'd want to wait at least a minute to stand a chance of getting closer to 93C/200F as your starting temp. After that, as you point out, other factors come into play. Hopefully cold water is not a big one right away, as it sinks to the bottom and the water to the GH is drawn off the top. And hopefully heating the metal isn't either if your Silvia is properly warmed up, or if you've pulled some blanks beforehand. And if you flick the steam switch at the same time as the brew switch...

I'd love to see charts of the intra-shot temp on Silvia with the steam switch on and off. Perhaps someone like Eric has already done this?

[Psyd]

My understanding is that the water gets hottest about 1 minute after the thermostat cuts the power to the heater. This is because there is residual heat in the element that continues to pass into the water during that time. (Maybe you could try brewing at this time for a little extra heat, Psyd?)

I'm pushing a bit further back every morning til I find a sweet spot. I've heard the same thing, but I'll have to see what happens

Seeing as 200F (a good average start temp for espresso) is 93C, and the heater is turned off when the water is 100C and then the water gets hotter than that for a minute, you'd want to wait at least a minute to stand a chance of getting closer to 93C/200F as your starting temp.

200F is a good starting point, and 100C is 212F*. If the boiler element cuts off at 212F, why would we wait to get to 200F, if the temp increases with waiting? It seems to me that the 212F cutoff would get you nearer to 200F at teh PF basket than letting it heat up further, neh?

Hopefully cold water is not a big one right away, as it sinks to the bottom and the water to the GH is drawn off the top. And hopefully heating the metal isn't either if your Silvia is properly warmed up

'Cool' is relative. I'm able to hold onto metal that's at 160F to near 180F (although, at the latter, I tend to juggle a bit) and I've developed 'hot hands' to the point where waiters freak when I take plates from them ; >. That being said, running 200F water over a 185F portafilter will soak a lot of energy from that water.


*100 x 1.8 + 32 = 212

[erics]

I'd love to see charts of the intra-shot temp on Silvia with the steam switch on and off. Perhaps someone like Eric has already done this?

Early on in the development of the thermocouple adaptor, I was running graphs on Silvia because that is all I had. I installed a simple switch to cut power to the heating element and mounted it on the side frame of the machine. The reason for doing this was that the Chinese PID I was using (no longer available) was unusually responsive and was unusually well tuned. The responsiveness was inherent and the tuning was a lot of luck and a lot of playing around.

The graphs are buried in here:

http://www.home-barista.com/forum...-silvia-t1352.html

I was sensing boiler WATER temperature and the machine could easily be back to Sv and stable within 5 seconds of pulling a shot. The temperature graphs would show a rising temp towards the end of the shot. When I cut the power to the heating element at the very beginning of the shot, the temperature graphs became essentially straight lines.

These graphs show Silvia's water temp variations with the 100 C thermostat:

http://www.home-barista.com/forum...out-pid-t4691.html

The most interesting thing to note, IMO, is that Silvia's grouphead temp rises about 10-15 F with a typical PID application. These "tests" were also done with a newer version of the same Chinese PID which was not as responsive and thus, I don't remember having to cut power to the element but I can't be sure of that. In any event, I think you would be pressed to taste the difference.

[ChrisC]

Well, it does get hotter when you wait, but then gets colder after the first minute. As you've pointed out, if the t-stat cuts the heater at 100C, which is 212F, it's already too hot at that point. So even though waiting one minute is going to shoot you even further up, eventually you'll hit 93C/200F on the way down. But then as you point out, there are a bunch of other factors that may be already cooling it as much as or more than it needs before it hits the coffee.

And of course, even if we figure out my perfect wait time, that won't work for you, with your individual thermostat, altitude, barista techniques, grinder, grind setting, blend/roast, etc.

Back to, what tastes good to you?

[ChrisC]

Thanks Eric -- I figured these existed. I've even seen the second batch before, but I must admit that often your posts are right at the threshold where I stop really understanding.

If I'm not mistaken though, your research seems to indicate that with a decent PID and a standard shot time of 25 seconds or so, the temperature at the coffee is basically flat. So there's really no need for me to be engaging the steam switch at the same time as the brew switch -- if anything, I may be increasing the temp over the course of the shot by doing so.

[erics]

If I'm not mistaken though, your research seems to indicate that with a decent PID and a standard shot time of 25 seconds or so, the temperature at the coffee is basically flat.

That's correct.

Where Silvia gets "messed up" is when you implant some steaming into the routine. As was originally posted by Mike McKoffee some years back, successive shots with Silvia tend to rise in temp - two shots back to back would probably be OK but when you are having a barista jam, trying to do 3, 4, 5 shots etc., the rise in GH temp will affect subsequent shots.

This rising temperature action would be most apparent if you had an unusually responsive PID and least apparent if you had a PID that took its time in returning Pv to the Sv value.

If you wanted to pull a shot after steaming, you need to flush about 4 ounces and then all will be OK - this being with a PID'ed Silvia.

[japa_fi]

Well, it does get hotter when you wait, but then gets colder after the first minute. As you've pointed out, if the t-stat cuts the heater at 100C, which is 212F, it's already too hot at that point.

Don't forget that 212F/100C in the boiler is not too hot. Water temperature drops on its way to group head. PIDs are usually set somewhere around 229F/109C, yet they result to about 205F/96C at group head (one example available at http://www.pidkits.com/thermofilter.html). Based on that, one would like to have temperature continue rise over 212F/100C

[ChrisC]

Yes, but I'm assuming that that 212F/100C is water temp INSIDE the boiler, or at least an approximation thereof. Otherwise it would be way too low. As you note, PIDs usually indicate much higher temps, but that's measuring the metal on the outside of the boiler, where the thermocouple is attached. Difference from the PID temp displayed to what you get at the GH has been approximated to be about 25 degrees F (your example lists 24). I don't think the water temp drops that much from inside the boiler to when it hits the coffee.

[Psyd]

Yes, but I'm assuming that that 212F/100C is water temp INSIDE the boiler... ... PIDs usually indicate much higher temps, but that's measuring the metal on the outside of the boiler, where the thermocouple is attached.

Ehm, isn't Silvia's t-stat also attached to the outside of the boiler? I'd suggest that either the t-stat is set to turn off when the metal that it is attached to reaches 100C, or that it is sufficiently offset to turn off when the water behind the metal reaches 100C. I'm betting that it's a stock manufactured part, and that the former is the case.
So, again I'd like to see the specs on the different iterations of the Silvia. you'd think with all the connected folk on this here forum, someone would be able to get a Rancilio rep to explain just which Silvia is which, and which changes were just cosmetic, which were bits, and which were functionality changes. Once we have a designator for each Silvia, we have a better method to compare. Stuff that worked really well on my 2000 Silvia (stick-on badge, and cursive 'Silvia' sticker underneath it) with her 110C t-stat probably wouldn't translate well to someone's 'yesterday' purchase.

[ChrisC]

This does exist, I've seen a post either here or on CG listing them, but I can't find it now.... Can anyone help?

(And I was assuming that the Silvia T-stat had an offset -- that calling it a 100C thermostat was because it was adjusted so that it turned off when the water inside the boiler hit 100C.)

[japa_fi]

Yes, but I'm assuming that that 212F/100C is water temp INSIDE the boiler, or at least an approximation thereof. Otherwise it would be way too low. As you note, PIDs usually indicate much higher temps, but that's measuring the metal on the outside of the boiler, where the thermocouple is attached.

With PID and silvia stabilized to 109c, I'm 99% sure the water inside is also 109c or pretty close. After all, the water is surrounded with metallic surface (=boiler) that is 109c.