boar_d_laze wrote: As it stands, as you warming the group with your first shot, the group is cooling the brew water. If you pull a successive shot after a brief interval, you'll pull with warmer water and the shot will be bitter. If you pull after a long delay, you'll pull with cooler water and the shot will be sour.

Hope this makes it understandable,
Rich

Yes - I understand. This is my first PID machine, so I didn't think that was such an issue with a DB. The first shot is always great, so I will have to know how long prior to pulling a shot.

I guess were I am lost is with a PID I would think if I flush right before I pull a shot with the Pro 700 the water used for the extraction would be the same as what the PID reads. However, seem like that might not be correct.

JavaRanger wrote:I guess were I am lost is with a PID I would think if I flush right before I pull a shot with the Pro 700 the water used for the extraction would be the same as what the PID reads. However, seem like that might not be correct.

The water going into the group is temped by the PID. The water coming out is temped by the group.

The group temperature is a function of the heat energy coming from the brew tank (which is controlled by the PID), water in the head's internal reservoirs, thermosiphonic flow, and any water you pump into the group with a flush or a shot. So, there's a lot going on.

What you want to do is to equilibriate the group head to the same temp as the brew tank, and then dial in your PID to whatever temperature is most pleasing for your beans.

Don't worry too much about the 198F Profitec recommends in terms of the PID temperature readout. It's obviously pretty close, but not quite right.

Parenthetically, and as you probably already know, the readout includes some offset, which may or may not be accurate and for that reason -- even if the group is in equilibrium -- doesn't necessarily reflect the actual temperature coming out of the screen. The best way -- maybe the only practical way -- to get the real skinny on espresso machine temp is to use a Scace thermometer.

The inference from your description is that the brew tank is set a little hot; and is tempered by an incompletely heated group for your fist shot.

What you want is a technique that will give you the same temperature no matter how long the idle between shots; and that means giving up your current first shot technique and integrating a warming flush before every shot.

Start by lowering your PID to 196F and pulling after a warming flush. Try a couple of shots (taste by small spoonfuls so you don't over-caffeinate), then -- if it's not perfect for temp -- dial-in by bracketing.

Not that it matters, but most light-medium and medium roast espressos dial-in in the 199F - 202F (actual) range; so 200F (actual) is usually a good start before you begin bracketing your way to temp nirvana.

In any case, once you have a temp which works for your usual coffees, you might want to adjust the offset so you get a readout which better reflects reality. Admittedly, calibrating your thermometer by palate is a bit bass-ackward, but it's cheaper than renting or buying a Scace device... and whatever works.

Rich

All the advice above from Rich and Merle has been spot on. I'll just add, as a previous PID'd dual boiler E61 owner, if you're really crushed for only a 30 minute warm up time, you might consider putting a dish towel over the group at the end of the night and leave it on until you're warmed up for those 30 minutes. Not having as much radiant heat loss will help with initial pre flush group stability and make the most of that short warm up time. 30 minutes isn't horribly short, but it's cutting it close.

The Group runs a little on the cooler side to what you want it to be at, so a warming flush is necessary or succesive shot would tend to taste somehow off, if you have set the temperature after how the first shot tasted.

If 198F tastes bitter after a warming flush, the offset should be lowered, but you'll need a Scace to really tell you how much. The offset is usually set too high, but remember the offset should reflect the temperature after a warming flush, not before

I flush for around 6sec (2oz) then leave the group for 30sec before I pull a shot, when I begin a new session

30min warm up time is a bit on the low side, give it 45min

Here's more about PID settings on this machine. There are instructions about making changes:
Profitec Pro 700 Review

canuckcoffeeguy wrote: 700 Review[/url]

Thanks, the machine is only a few months old, it was bench tested, so I would think the PID settings or correct...I am hoping it just a problem with the part time Batista that operates it...

Well, yes and no; and maybe no and yes.

The "problem" isn't really a problem, the problem with over and under extracted coffee (bitter and sour respectively) stems from a lack of sophistication on your part; one which you can easily and quickly rectify by incorporating a warning flush and by learning to temp by taste instead of readout.

You taste with your palate not with your thermometer, so dialing in for temp properly should always be palate driven.

Whether or not the PID accurately reflects the temperature of water at the screen in a properly equilibriated machine is a different and far less important question. The PID temperature sensor measures temperature in the brew tank, not at the screen. The head is responsive to environmental conditions (like room temperature), whether or not it was ever properly warmed, how long it's been idling, etc.

At the risk of repetition, let's return to first principles: You have to understand that there's no one single temperature that's right for all coffees. You'll have to dial in every new coffee and possibly for every coffee as it ages. Sometimes dialing in is simply tasting and smiling and doesn't require you to make adjustments but sometimes you'll need to adjust.

That's just how it is when you have a good palate (which you do or we wouldn't be having this conversation), one that discerns the difference a few degrees Farenheit from ideal makes. The penalties are some extra technique (easy), and a bunch of long-winded explanation to help you understand why; the payoff is greater enjoyment.

Rich