How did you get 9 seconds of p/i? I thought the limit was 8. Have you tried a higher line pressure yet? Using the 3 sec./25 psi setting I've yet to get any taste improvement, usually just the opposite. Same for the pour; my non p/i shots look & taste better but I seem to be in the minority there. I'm going to try a higher line pressure & see what happens.

If you have a bean/blend dialed in without p/i how much do you change the grind for p/i?

John, you are absolutely right on the 8 seconds of maximum preinfusion. My pics should read 0,3,6 and 8 seconds. As to the grind I found I had to grind a pinch coarser as I added each 3 second bump to keep the same basic shot time and volume. I did lose it on the 8 second pour though. I need to work with this a bit more. Also I did crank up the line pressure a while ago before I started on this review. Had to play with the timing from my well pump to get up to 40 psi (kick in the pump to fill the tank then pull the shot). I wasn't getting the same consistency as the 25psi pulls so I backed it back to 25psi.

Ooops, ran out of coffee It's amazing how quickly you can burn through a pound of coffee when your pulling shots like this. Ordered a bag of Toscano from CCC. Should be in tomorrow and we'll be testing again.

Ian

PS In the spirit of full disclosure, I did save enough for a couple of shots to get me going tomorrow morning

Pulled some nice shots of Toscano on both the VII and La Valentina machines today. I had to tighten up the grind a small amount for La Valentina to match the pour times and volumes on the VII.

One thing I noticed when I was working with the machines today was how quiet the VII is. I had experienced some fan noise on my earlier version but the newest model is incredibly quiet. The VII turns on a small muffin fan to cool the SCR when the steam boiler is turned on. I believe Chris fiddled with this a bit on the new release. Also no clicking noises as compared to the Siria pressure stat on La Valentina. Not a big problem but my wife did ask what "that clicking noise was" she kept hearing in the kitchen.

I did measure the duty cycle on the group and steam boiler versus La Valentina. The pressure stat on La Valentina turns the heater on for 10 seconds and off for 50 seconds. The group heater on the VII is on for 15 seconds and off for 2 and a half minutes and the steam boiler heater is on for 10 seconds and off for 90 seconds.

The VII uses a thermo probe instead of pressure stat to turn on and off the boilers. The group thermo probe has 0.5 degree Celsius sensitivity, an improvement over the one degree in the earlier incarnation. This thermo resolution translates into solid temperature stability especially for a home machine. Chas Rimpo has done some excellent work on VII thermo stability measurements noting less than one degree Celsius of variation over the course of five shots in his tests. I believe I could get close to this on the HX machine but I would have to use the meter to get there.

One other advantage I find with the double boiler is that you can turn it off. I personally drink mostly espressos during the day but my wife likes her cappuccino in the morning. I pull the caps then turn off the steam boiler for the rest of the day. A little greener way to go.

This brings up the method of pre infusion programming. At the moment, once set, pre infusion works on both dispensing buttons. When the steam boiler is off, I use the group to flush the portafilter. It would be nice to be able to program pre infusion for each dispensing button separately. This way you could leave one for rinsing and back flushing and one for your usual pulls.

Cheers

Ian

I had time to do more detailed steaming performance tests today. I used a Fluke 52II with a type K thermocouple for the tests. I used both the 0.9mm and 1.2mm tips. I did three rounds of tests and averaged the three to get the final reading. I started each session just as the steam boiler heater had turned off. I used water instead of milk. Cooled down the water from the tap with ice and then poured off the appropriate amount of water and waited until we hit 40°F.

I measured the time to take the water from 40°F to 160°F. I actually like to stop my milk a bit earlier but several of the other bench tests have been done to 160°F, so for comparisons sake that's where I ended up.

Below are the results. My takeaway from this session: you will not need to worry about steaming performance with this machine and the smaller tip is a little easier to deal with when steaming smaller quantities of milk.

Quantity    1.2mm Tip       0.9mm Tip

8 oz        23 seconds      33 seconds
10 oz       27 seconds      41 seconds
12 oz       30 seconds      49 seconds       


Microfoam wise, I do like the smaller tip. I had better success with the extra time the smaller tip gives you.

Cheers

Ian

Decided to focus on pulling a range of shots today: singles and doubles. I did some triples as well but since there is no commercially available source for the baskets, I'll leave that to another post and a different thread.

For the most part I tend to pull more doubles than anything anyways. Some triple ristrettos when I'm feeling a bit decadent and single when I have some interesting single origins to try.

I had some Toscano left over from my visit to Counter Culture Coffee last Friday so stuck with that for the session. I started with the singles. I ended up settling on 9 grams in the basket and pulling at 92°C for about a 25 second pour. I had to loosen up the grind a tad when I moved to the double basket to get the same pour time. Below is my typical setup for straight espressos. Followed by a picture of the single.





It did take me a couple of tries to get the grind dialed in. As I said it was a notch finer than the doubles I had been pulling. To my surprise the Toscano tasted pretty darn good as a single. It was a tad brighter or more acidic than I am used too but that was not a bad thing for this coffee. I may have to use this single basket more often I kept the pre infusion at 3 seconds. I didn't try moving it around too much today because I have been getting some pretty good pours at that setting.

The doubles went as they have been for the last several weeks. Just consistent as heck. I did loosen up the grind a notch. I pulled 16 grams of coffee into a double basket for 25 seconds again at 92°C. Coffee tasted great, a rounder mouth feel than the single and more of the base notes like chocolate but less of the acidity than in the single.



My takeaway here is just how consistent this machine is across the full volume gambit. With a little bit of tweaking you can pull consistently good shots in either the single or doubles. Expect the singles to be a little brighter and the taste to soften up as you go up the dosing curve.

Cheers

Ian

One of the big differences between my earlier VII and the latest from Chris is the ease of programming the temperature offset for the group. Normally this is done by the shop so you shouldn't have to mess with it at home but once an engineer always and engineer.

The offset basically corrects the reading on the front panel for the difference in temperature between the group boiler and the actual group temperature. So increasing the offset is in effect increasing the temperature as measured at the group and decreasing the offset is decreasing the temperature as measured at the group.

The offset can be set from -8°C to +8°C on the latest vintage of the VII. Setting the offset requires a good measurement device to start with. I used a Scace to adjust the offset on my machine.



Setting the offset is pretty straightforward: with your machine in stand by mode press and hold the boiler button for about ten seconds. The boiler light and stand by light will start flashing. To increase the off set from +0/+8 degrees you push the single cup button to decrease the off set from -0/-8 degrees you push the double cup button. Each time you push button it will decrease/increase by one degree up to eight times.

To hit a 93°C group temperature as seen on the display I ended up setting the offset to -2°C.




Not much more to it than that. The double boiler configuration and accurate thermo probes make for good thermo stability from this machine.

Next step. Get Dan and a few of the local coffee geeks over here for a taste test between the VII and La Valentina.

Cheers

Ian

One accessory that I can't live without on the VII is the seven day programmable timer. I had this on my old VII and it wasn't installed on the new model I am testing. Boy do I miss it. The timer is a great compromise between leaving the machine on all the time: easy but a bit wasteful electricity wise or remembering to turn it on 40 minutes or so before you are going to use it: requires a better brain than I have but is a greener way to go.

The timer is relatively easy to setup (manual in hand) and allows for turning on and off the machine up to three times a day for any of the seven days in a week. For me the seven day feature is moot since I get up every day at the same time anyways. For the later risers on the weekends this is a nice feature to have.

The timer comes with a backup battery so power outages shouldn't impact your settings.



The timer is attached to a small cable that plugs into the control board of the machine. It would have been nice to have the timer integrated with the front panel some how but I'm sure controlling costs has something to do with Chris's decision and I understand the rational for making the timer optional: some people will just leave the machine on or turn it on when they need it. I keep my timer hidden behind the machine since I don't use that clock and I don't change the programming very often (read never).

Cheers
Ian

Ian, the timer has one downfall - incredible price. I was considering getting it, but in Europe it costs even more.


(now, let's compare it to something )

There definitely is that. At last look Chris was selling them in the US for $195. Still for me it removes alot of hassle and it was worth the investment. I'm sure there is a lot of DIYers out there that could do it cheaper, I just don't have the patience nor the time.

Cheers

Ian