Hello all! Does a PID'd Silvia need a cooling flush? After it's been idle for any length of time, I get a few seconds of steam. If I flush the steam and start the shot as soon as it comes back to 230 degrees, I still get about the same amount of steam. One thing is for sure, the shots taste A LOT better if I do the cooling flush, but this drops the temp reading down to about 203 degrees at the start of the shot. I don't remember ever reading anything about PID'd Silvias needing to do this and was wondering what's up? Thanks!

230?

I have my PID set between 217-221 depending on the bean. You should set your PID by taste. Try setting it at 215 pull a shot, 216 pull a shot and on up. I think you will find your PID is set too high. Good Luck


h

Really? It's been a few years since I did the PID and at that time 230 degrees was the most common setting people were using, by far. At first I played with it a few degrees each way and didn't taste any difference so I just left it there, not really having any time for experimentation. However, after getting my Tea II, I have of course had to learn the importance of the flush hence my sudden awareness of the Silvia problem. I'll try the lower setting. What I would REALLY like to do is get another E61 machine to replace the Silvia. I'm not sure what I'd do with the Silvia, though. Maybe save it for backpacking. Seems like it would be perfect for that.

TonyJ wrote:If I flush the steam and start the shot as soon as it comes back to 230 degrees, I still get about the same amount of steam. One thing is for sure, the shots taste A LOT better if I do the cooling flush, but this drops the temp reading down to about 203 degrees at the start of the shot.

I don't completely understand what you are describing here. Are you saying that the PID display drops nearly instantly from 230F to 203F as soon as you start the shot? That sounds very drastic and is not something I'd expect to normally see.

In answer to your question, I have not studied this exhaustively. But I did find that if you are pulling a series of 3 back-to-back shots then a short flush between shots gave much better temperature consistency. Without the flushes, each successive shot was a little hotter than the previous one. With the flushes, the shot temperatures were pretty consistent.

I also concluded that the flush is not as critical for "walkup shots" after the machine has been idle for awhile and is no longer under the influence of a recently pulled shot.

Jim

The display starts at 230 degrees. I start the flush. By the time the steam stops (a few seconds) the temp is down to about 203 degrees. If I wait until the temp gets back to 230 and push the brew button exactly when it hits 230, then I still get about the same amount of steam. The ONLY way I can avoid steam is to either drastically lower the set temperature, or pull the shot as soon as the steam ends (at 203 degrees). The Silvia is at work, and I'm very rarely there now because I'm working like a madman to finish building my house before the construction loan closes in a few weeks. The Tea is at home where I need it in my brand new kitchen. I have had to work completely through the night on several occasions in order to get things fininished on time so various crews could do their jobs. Couldn't have done it without coffee.

TonyJ wrote:The display starts at 230 degrees. I start the flush. By the time the steam stops (a few seconds) the temp is down to about 203 degrees. If I wait until the temp gets back to 230 and push the brew button exactly when it hits 230, then I still get about the same amount of steam. The ONLY way I can avoid steam is to either drastically lower the set temperature, or pull the shot as soon as the steam ends (at 203 degrees). The Silvia is at work, and I'm very rarely there now because I'm working like a madman to finish building my house before the construction loan closes in a few weeks. The Tea is at home where I need it in my brand new kitchen. I have had to work completely through the night on several occasions in order to get things fininished on time so various crews could do their jobs. Couldn't have done it without coffee.

I did some measuring with my PID Silvia (using Love PID) with a Scace device
I found out that over time the brew temp goes up while the PID shows the same temp (210 in my case)
The work around was the same technique you described here - flush some water (use it to heat the cups), the PID shows lower temp, then I wait for the PID to stabilize and pull my shot
That way I can get constant temp in the cup (I'm aiming for 195F with Terroir coffees)

I think the problem is that the brew head get warmer as the time passed by while the water comes with the same temp, so in fact you are using the flushes to cool down the brew head (E61 style)
Like Jim I also tends to flush some water between shots (use them to clean the head/PF) which lower the temp displayed on the PID and then pull the next shot when the PID stabilized

Using this technique I was able to verify repeatable temp using the Scace device

/gabi

TonyJ wrote:The ONLY way I can avoid steam is to either drastically lower the set temperature, or pull the shot as soon as the steam ends (at 203 degrees).

Your local boiling point is probably in the range of 209F. When you combine that with a PID setpoint which may be a little on the high side, then getting steam at the start of a flush isn't really surprising.

Exhausting the boiler's supply of stable, heated water by flushing down to 203F might not be the ideal solution.

Here's what I'd try instead:

1. Reduce your PID setting to 228F or 226F.
2. Do a very brief flush right after you remove the PF - say 2 oz
3. Grind, dose, tamp and lock the PF in place
4. Make sure the PID has stabilized at setpoint again
5. Open the steam wand briefly to purge the hottest water/steam from the top of the boiler.
6. Immediately pull your shot after closing the steam wand.

Due to variations in PID calibration, sensor type and location, etc. it is hard to compare setpoints directly. So the 230F you are using may indeed be just right for your setup. OTOH, in my experience, this is on the high end of the "good" range.

Jim

Thanks for the tips. Someday I'll be able to afford a Scace device and finally get this all figured out. In the mean time, what I REALLY need right now is a Bosch 1250DEVS. I've got an incredible amount of sanding to do.

I wouldn't look blindly on the recommended 229F/109c PID setpoint for silvia. I have set my own to 215F/102c.
When I got my PID and set it to 229F/109c I got steam from the grouphead. Ie. water was hotter than 212F/100c. I lowered the PID temperature until the point which I thought there was no more boiling water coming out. Once I reached that point, I lowered the PID temp by 8f/4c to reach the often mentioned 93-96c temp area. I've got excellent results with my current PID settings. Later I bought a cheap digital thermometer with a want that I can push partially in to the hole where the hot water comes to the shower screen. From my measurements (which are by no means accurate), my PID setting produce water that measures about 94c at its hottest. Based on my experience with the thermometer, it's reaction speed, etc. I'm quite confident that the actual water temp is in 94-95c range.

So why do I get "right" temperature with PID setting that is much lower than the generally thought "right" setting?
Originally I thought it was because of the high ambient temperature of my kitchen (about 81-83f/27-28c). But now when the weather has cooled down since summer and my kitchen temp is normal (72f/22c) there has not been a need to raise the PID setting more than 2f/1c. So my guess is that it is either something to do with this silvia being new model (there should not really be any difference), or the thermocouple in my PID just shows lower readings, or perhaps it's the cosmic rays etc.
Anyway, I don't care what the reading is as a number value as long as I know what value gives me excellent results!



-Jani

Ps. Jim: When you let out the heated water from the steam wand, do you use the pump or do you just open the steam wand and let water come out at its own pressure?

japa_fi wrote:Ps. Jim: When you let out the heated water from the steam wand, do you use the pump or do you just open the steam wand and let water come out at its own pressure?

Hi, Jani -

No pump, just let the pressure in the boiler do the work.

Jim

PS - Regarding your PID setpoint: I have no doubt that it is the cosmic rays