bernie wrote:FWIW, I have an idle LM 4group that is scheduled to have dual PIDs installed this summer. Not sure when I will get to that as we are putting the finishing touches on a new bakery and bagel kitchen. It will be kicking my butt for a while I'm certain. But, when the machine is done I will offer it up for such a test. It is one big muthah. I'd need someone to arrange moving it to wherever the testing takes place. Maybe a road trip from someone.

To make it even more fun, I could put the real-time brew temp probes in it.

barry wrote:To make it even more fun, I could put the real-time brew temp probes in it.

Alright! In the vernacular of the under 50 set I believe I am "down" with that idea. I'll duct tape the 4group to the top of my wifes Merc Gran Marquis. She will be heading to Kansas City for a 90-day consulting gig. If you could arrange to meet her with some goo-b-gone type stuff to get the duct tape remains off the roof that would be great. There shouldn't be a bug-splatter problem this time of year, but you may want to invest in a bottle of salt-spray remover. Those midwest snow blizzards can make a mess out of an exposed LM.
Bernie

bernie wrote: The first thing that comes to mind is the effect of the exposure of the dry puck to the heat of the group head once the pf is locked. At what point does the difference in one degree F. increments become less of an impact than that dwell-time? If I look at it in terms of percentages the difference between 199F and 200F is one-half of a percent. But if you look at the dwell time of exposing the dry puck to the group head of just a couple of seconds the difference can be 200 percent. Is exposing the puck to a temp of 200F for twice the amount of time as important to consider as one-half percent difference in temperature? It seems so to me.

I tested this a few years ago... pulling numbers out my ass, iirc, the top surface of the puck took about 30 seconds or so before it exceeded 100F. I was playing with the "immediate brew" requirement in the competition rules. Data is around here someplace. The tests should probably be re-run in my copious spare time.

bernie wrote: I'll duct tape the 4group to the top of my wifes Merc Gran Marquis. She will be heading to Kansas City for a 90-day consulting gig. If you could arrange to meet her with some goo-b-gone type stuff to get the duct tape remains off the roof that would be great.

If you rent a car and pay for the insurance, then you can just peel the duct tape off and not even worry about taking some paint with it!





Did you ever meet Sammy Olivieri?

bernie wrote:If I look at it in terms of percentages the difference between 199F and 200F is one-half of a percent.

As far as I can tell, it doesn't make much sense to talk about percent change in temperature this way when the 0 point of the Fahrenheit temperature scale is arbitrary.
This is really not very relevant to the discussion, but I couldn't restrain the pedant within me.

Navin

I quoted this from another thread found here: Barefoot Espresso Bigfoot

I posted it here so as not to hijack the subject matter of the original thread.

The emphasis was added by myself -

roblumba wrote:Anyone else try Bigfoot. I bought a couple pounds the other week for the first time. I was getting good shots from it and it was definitely chocolaty. But about halfway through the pound and decided to try upping the temperature by .6F on the GS3 and wow! Chocolate really came through, especially in milk. It was a bit heavy for espresso, but It was like having a Mocha Latte in milk.

My wife doesn't get impressed by espresso very often, but she was genuinely amazed. I was actually suspicious for a moment that they had substituted some cocoa beans in the blend, but I reminded myself that it would have gummed up my grinder.

That was definitely something unexpected from an espresso blend. Definitely worth trying again.

I find this statement interesting because many individuals have resigned themselves to accept that temperature is not as important as it was conveyed to be a couple of years ago, and several statements have been made regarding that most people are unlikely to taste a temperature variance of less than two to three degrees F.

My first questions go to Robert - Was this change in taste profile repeatable for subsequent shots? Also, do you feeling that your dosing and distribution are consistent? I'm not trying to be critical of your skills, just wondering if another factor is responsible for change in taste profile.

To Greg Scace, Andy Schecter, Barry or any other espresso PhD's out there - does anyone know what the error limits of the GS3 electronics are, or is that proprietary stuff that we just won't know? I'm just curious if a change of 0.6 degrees F can actually produce a change of 1.5 or 1.8 degrees (or whatever).

Matt

Matthew Brinski wrote:I find this statement interesting because many individuals have resigned themselves to accept that temperature is not as important as it was conveyed to be a couple of years ago, and several statements have been made regarding that most people are unlikely to taste a temperature variance of less than two to three degrees F.

I think this is extremely blend-dependent. Variation in the taste of Schomer's blends is probably observable at a few tenths of a degree F. A mainstream blend like Black Cat is probably a lot less sensitive.

Matthew Brinski wrote:To Greg Scace, Andy Schecter, Barry or any other espresso PhD's out there - does anyone know what the error limits of the GS3 electronics are, or is that proprietary stuff that we just won't know? I'm just curious if a change of 0.6 degrees F can actually produce a change of 1.5 or 1.8 degrees (or whatever).

Not a PhD, but I don't think the limitation is in the electronics, it's in the swirls and eddys of hot water in the machine. The early GS3 prototypes that Greg and I tested in 2005 were marginal when it came to pulling consistent shots at 0.5F accuracy. Presumably the production versions do better.

AndyS wrote:I think this is extremely blend-dependent. Variation in the taste of Schomer's blends is probably observable at a few tenths of a degree F. A mainstream blend like Black Cat is probably a lot less sensitive.

Just thinking here, but it is unlikely that taste changes relative to temp occur regularly.. meaning that going from 198F to 198.3 could produce a more noticeable change then going from 198.3 to 200, for example, or that a particular flavor is only produced at 200 while others can be brought out by anything within the normal temperature range... thoughts? (or better yet, experiences? )

Henry

AndyS wrote:Presumably some blends (like David Schomer's for example) are more temperature sensitive than others. But no one (to my knowledge) has published a legitimate blind tasting experiment showing that 1F differences are detectable, much less 0.1F differences.

Guys,

Interesting to see how the thread develops into discussions about laws of physics.

The question remains ...

Personally, I do not have the resources to do implied tasting experiments, but would expect them to be revealing of at least some discriminatory capacities in coffee tasters.

Some of the physics part of the debate, I would say the following about:
- if you want a 1F or 0.5F precise/stable espresso machine, what should be your regulation precision requirement? I would say in the 0.1F range.
- does it matter if 198.3F is exactly 198.3F, or your measurement instrument is able to exactly measure that number? No, it only matters it has very precise repeatability. Your Fluke may tell 197.8, and that is not a problem as long as it does give that number each time the temperature is the same value, time and again.
- does a PID help you get your shot at exactly the temperature read on the PID? There likely is a big difference in inter-shot and intra-shot stability between a 1.5 liter boiler pro-sumer machine versus an 11 liter boiler commercial one. Saturation of the group will no doubt be a discriminating factor as well. I think.

So, before setting up a (double? blind?) tasting experiment, these factors need to be controlled.
Having tracked this forum, I know some of you are well able to do that.

It would really be interesting to see what these some of you would experience in this desired tasting experiment.

Regards,

Peter
Netherlands

I was just pointed out I had a open question about the .6 degree change that I claimed to have tasted.

A double blind taste test would definitely be a good idea. I'm probably not the one to organize it considering that I have little experience in tasting, I don't know how to document things like that.

On several ocassions, when I do change the temperature, I've noticed the change in taste. And usually I change by at least .6F, sometimes .9F or 1.2F or more. But usually I can tell if I've gone a little too far, and reducing by .6F can make a big difference in my opinion, especially when it's just a little too low or too high.

I keep the shot volume and extraction time fairly consistent. Usually around 28-30 seconds at 1.75 ounces. I've been using the Naked Portafilter and the standard double spout. In checking with the naked portafilter, I see a fairly consistent pour. Granted, not textbook pours, but nonetheless after watching several dozen, they are very close to the same.

I reproduced the chocolate intensity on two consecutive days, but this was at the end of the lb. So it's hard to say if rest time after roast had anything to do with it, but it seemed that the chocolate came out at the same time that I upped the temperature .6F. Perhaps it was a combination of roast rest time and the temperature change.

Actually, I pulled out some Bigfoot Espresso this morning and I actually forgot to adjust the temperature up again. The chocolate notes are not really there right now. I'll try it again this morning and see if I can repeat it from Bigfoot that has been sitting in the freezer for a couple weeks.