Dennis, the way the controller on the Brewt the higher (the magnitude) of the offset (it's a negative number) the higher the brew boiler water temp is driven before the heaters shut off. This is b/c the offset is a reflection of the temperature lost as water travels from the brew boiler to the p/f.
For instance in a case of a 96 C setpoint and a -8 C offset we are essentially telling the controller to "give me a temperature of 96 C at my p/f assuming a temperature drop from the brew boiler of -8 C". Thus it will try to get the water in the brew boiler to an actual operational temperature of 104 C. So if we were to increase the magnitude of a -8 C offset to, say, -18, it will try to drive the brew boiler to an operational temp of 114 C. However this does make me wonder, though, that since the sum of our desired brew temps plus the typical offsets are very close to or exceed 100 C (e.g. brew temps of 95-7 C + typical offsets of, say, 6-7 C), might it be impossible to get to our desired brew temps so long as the entire brew path does not constantly stay under pressure from the very moment water leaves the brew boiler? That is until all of the space from the output of the brew boilers all the way to the cavity above the coffee puck are filled with water and pressurized, is it not guaranteed that the water in there will be a fixed offset below 100 C rather than a fixed offset below the actual brew boiler water temperature? What I'm picturing is that any water leaving the brew boiler, even though it is being pumped, is seeing very little pressure, thus causing it to instantly give up its heat as steam leaving behind water that is at most 100 C. But as it travels through the brew path it will lose more heat and drop, perhaps, considerably below the desired brew temp until the water path can be re-pressurized to prevent steam to escape; even then the (cooler) water already in the brew path needs to be displaced before any >100 C water can flow. If correct then this may imply that given, say, an intrinsic offset of -x degrees, then any target brew temp above 100-x is not possible except for longer shots where the later fraction of brew water can be expected to be at a higher temperature. Since I only do very short ristrettos, am I condemmed to have brew water at the most at a temperature of 100-x C? Just wondering... Any thoughts? --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Brewtus" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/brewtus?hl=en -~----------~----~----~----~------~----~------~--~---
