pizzaman383 wrote:Does the Profitec Pro 700 use the steam boiler to preheat water entering the brew boiler?

I believe that it does not...

erics wrote:What the PID reads is only sorta relevant. When you have about 30 grams of liquid going up against ~ 4200 grams of brass, who ya think is going to win?

Got it. I assume that the exposed E61 is really a heat sink (although quite close to brew temp). The group head is slightly below brew temp. The brew boiler is slightly above brew temp. Water pumped from the brew boiler is temperature buffered by the E61 and the right temp water comes out?

Yes, you "got it".

For reference
just got an answer from Profitec. Looks like d=8 is the oficially recommended value for machines operating in Celsius. D=4 is supposed to be fine for Fahrenheit.

I asked Profitec for a more detailed evaluation of how t1 translates to brew temp, but their tech guys are on summer holidays so will have to wait a bit.

As for my settings I still havent found the sweet spot :/

Okay then... deep breath and then the really potentially dumb question. If one were to insulate the outside of the E61 group head for a double boiler, couldn't you achieve similar thermal dynamics to a saturated group. That is:
1. Group head that is similar temperature to the temperature of the water in the brew boiler;
2. Minimal offset on PID (i.e. temperature in the brew boiler not too different from desired temperature at measuring point where the water hits the coffee puck); and
3. Greater thermal efficiency, and reduction in thermal losses.

This thread from 2005 starts going in this direction:
E61 Thermal Analysis Questions

Cheers,
T

kwantfm wrote:Okay then... deep breath and then the really potentially dumb question. If one were to insulate the outside of the E61 group head for a double boiler, couldn't you achieve similar thermal dynamics to a saturated group. That is:
1. Group head that is similar temperature to the temperature of the water in the brew boiler;
2. Minimal offset on PID (i.e. temperature in the brew boiler not too different from desired temperature at measuring point where the water hits the coffee puck); and
3. Greater thermal efficiency, and reduction in thermal losses.

This thread from 2005 starts going in this direction:
E61 Thermal Analysis Questions

I'd have to see some values, but I suspect that compared to a brief warming flush, insulating an E-61 is an enormous waste of time.

• 1. "Similar temperature" is accomplished somewhat by the thermosiphon flow which exists at idle; and second with a warming flush by water which is precisely at brew water. How much accuracy do you really need?
  2. Remind me. What's the problem with offset? You don't need much offset anyway, since the brew boiler is -- or should be -- set to hold water at brew temp.
  3. "Thermal efficiency..." So?

If the underlying idea is that a machine can be dialed in for temp on the basis of someone else's recommendation -- the roaster's for instance -- it's not a very good one. Because there are so many contingencies temping is and should be palate driven, not by the numbers.

Rich

Offsets are typically a sign of cooling by the ambient air. And ambient air temperature varies, so you get more temperature inconsistency. Insulation reduces the effect, as do saturated groups, "group mounted to boiler" and thermostatically heated group designs.

On the other hand, a thermosiphon loop fed by much greater than brew temperature water (ie, HX) might be perfectly balanced at some combination of room temperature and flush time and insulation might make things worse.

As Greg Scace said:

while the e-61 group has a pretty revered status, it's the wrong group to use in situations where you have the group temp and boiler temp close together, such as in the Brewtus or Chris's Coffee's new double boiler machine. But it sells machines

jonr wrote:As Greg Scace said:

Thanks. I suppose that Greg pointed to the logical extension a while ago.

Hello everyone! I just purchased the Profitec Pro 700 as my first prosumer machine. I have confirmed that my PID settings match the manufacturers recommended settings for fahrenheit however, reading over this thread, it looks like d = 4 should be the value when using fahrenheit. Can someone confirm this? Unfortunately, I don't have any gadgets yet to play with settings. Thanks!

espressom8 wrote:...reading over this thread, it looks like d = 4 should be the value when using fahrenheit. Can someone confirm this?

The PID settings instructions provided by the manufacturer indicate D = 8.