Thursday, August 16, 2012

Descaling the La Marzocco GS/3

Descaling is not the best thing you can do for your espresso machine and descaling can cause problems with clogged pipes and valves. If you are unsure on how to do this I would recommend sending the machine off to professional services. They would then unmount the boiler(s) and separately descale them with acid.

Always use a good water filter to avoid having to descale in the first place.

Please follow the below procedure at your own risk.

Machine cold and switched off.

1. Start by loosening the expansion valve situated in the right side just above the drip tray. Loosen by turning the brass “pipe” counter clockwise. No need to totally unscrew this.


2. Unscrew the brew head cover and loosen the bleed screw. Now the water should run freely from the brew boiler via the expansion valve into the drip tray.

3. When the brew boiler is drained, tighten the bleed screw and expansion valve again. The expansion valve should not be fastened all the way  -  see 8.
4. Prepare a descaling solution in a bucket consisting of 3 liters of water and 60 grams of biological citric acid. There should be enough to descale both the brew and steam boiler.
5. Unscrew the left panel.
6. A. If you have a your machine connected to your home water supply then remember to shut off the water beforehand. Disconnect the machines inlet hose from from your water filter.
6. B. If you are using the machines integrated water reservoir, unscrew the silicon hose from the pump and attach the stainless steel braided inlet hose that came with the GS/3.

7. Place the inlet hose in the bucket with descaling solution, turn on the machine and activate the pump (Continues brew button)
8. Stop the pump when the descale solution starts flowing from the brew head. Loosen the bleed screw carefully and activate the pump. When the water starts leaking from under the screw head, tighten the bleed screw. While the machine is warming up, the pressure within the brew boiler will increase and this is where the expansion valve must ensure the pressure does not exceed 12 BAR. The expansion valve must therefore be tightened (or loosened) until the pressure gage shows 12 BAR or just below. Turn off the machine again.
9. Drain the steam boiler using the inlet hose (unscrew from pump) or other available hose that fits.
Mount the hose on the drain pipe and open the ball valve to drain the steam boiler. Be careful not to scold yourself and avoid water running into the brain box underneath the steam boiler.

10. Once the steam boiler is drained, shut the ball valve and unscrew the drain hose. The inlet hose is then reattached to the pump (if ever unmounted) and the other end is placed in the bucket with descaler. Turn on the machine. The pump will start auto-filling the steam boiler now using the descale solution. Let the machine warm up as normal and let it descale 60-90 minutes. Optionally run some water/descaler through the steam wand and hot water wand.
11. Now flush the brew and steam boilers using the same procedure as above by draining and flushing the boilers with fresh water 3-4 times. Taste the water from the steam boiler to determine whether it should be flushed further. Taste the water from the brew boiler and continue running water through the brew head until the water no longer tastes sour.

Tuesday, May 15, 2012

New Steam Wand for the GS/3

As mentioned earlier I was most unsatisfied with steaming on the GS/3 with the no-burn wand. Not that it lacks steam power but the steam is wet and you need to purge a lot of water from the wand before steaming and as result I was never able to produce good micro foam. So I went ahead and ordered the newer version "burn-me" wand from the Danish La Marzocco Importer.
The wand or rather all the parts came with the mail today. I had to assemble the wand from different parts which was confusing at first as the LM exploded diagram that comes with the parts, is not precise on how to assemble this in "IKEA style". I also managed to install it in the machine using the Chris Coffee Service assembly video on YouTube: http://www.youtube.com/watch?v=QrJ81UG9n_c  - Excellent video!!


So, has the steaming improved?  Most certainly, yes!

You still have to purge water from the wand before steaming and whether it's less than before I'm not sure. What I am sure of is that steaming improved instantly and I had the nicest micro foam in my first attempt. It was like night and day!
The improved steaming capability could also be contributed to the 4-hole steam tip which seems a lot better than the stock 3-hole my machine came with.

Wednesday, May 9, 2012

New baby!


Four years with my beloved ECM Giotto has come to an end. It has been a wonderful journey and the coffee has been great but when I recently had a good offer on the espresso machine of my dreams, I just could not pass. My kitchen counter now stars the much coveted La Marzocco GS/3. The machine is from 2008 (S/N 0315) and the former owner has not been using it a lot. In fact it's still using the original brew head rubber gasket which is still relatively fresh and soft.


First impressions:

So does it brew better espresso than the Giotto? No Sir, it does not. Once you nail it with all the cooling flushing and the works, the Giotto makes excellent shots. The GS/3 just does it much more consistently. It's almost too easy ! Except for one thing; Steaming! The machine has massive steaming capability and you will not run out of steam but I must say I made better micro foam on my Giotto. The milk tastes great but it is near impossible to get bubble free micro foam and believe me, I have tried !! You need to purge quite some water from the wand and the steam is not completely dry. I should mention that my GS/3 is equipped with the no-burn steam wand as the early models and I believe all European GS/3's now ships with the "full-burn" steam wands largely due to the same issues I'm experiencing. I'm going to order the newer version steam wand to improve things on the steam side.
As I was not sure about the exact history of the machine I went ahead and descaled both brew and steam boilers and luckily there were no scale what so ever. Opening the machine in order to descale the steam boiler also allowed me to take a closer look at the internals and I must say that the LM guys really shoe-horned a lot of high end espresso machine technology into a relatively small case. After descaling I removed the water reservoir which is located behind the drip tray and hooked the machine up to the mains water supply (via Brita softening filter) and installed the waste drain.
Build quality is very good except for at couple of things. The drain box itself is good quality and with great capacity but it's loose at sits askew. Later models have tray locking taps under the drain box taking care of that problem. Also I have noticed that the drip tray top (rails) design does not drain too well and water will spill. The craftsmanship of the drip tray is not up to standards with cutting sharp edges and the before mentioned spilling. Again this has been changed on later models.

Stay tuned for more updates!

Thursday, March 1, 2012

Eliminating the guesswork when flushing a E61 group.

With Eric S temperature Adaptor (or the Danish equivalent "Thebat18 Device") you are essentially eliminating the guesswork of how much to flush in order to achieve the correct brew temperature on an E61 group based espresso machine.

The two preferred methods of flushing E61 group using Eric S Temperature Adaptor are the so-called Flush-and-Wait (Rebound) and Flush-and-Go methods.

For the Flush-and-Wait method you flush the group well below the brew temp then pull the shot when the thermometer is a few degrees Celsius below the brew temperature. The few minutes after the flush will heat the water in the heat exchanger (HX) to over brew temperature. This super-heated water then cools back down to brew temp when it hits the group which is cooler than the desired brew temp. Therefore you should deduct 2 degrees Celsius from the thermometer reading to get the actual brew temp. 
When using the Flush-and-Wait/Rebound method on my Giotto Classic with a boiler pressure of 1.2 Bar I flush until the thermometer shows 86 degrees C, then wait a couple of minutes (time enough to grind, distribute and tamp) until the thermometer reads 92 degrees C and then brew. The temperature should land between 96-96.5 degrees throughout the shot meaning an actual brew temperature between 94-94.5 degrees C.

With the Flush-and-Go method, the group will be a few degrees Celsius hotter than the desired brew temp.  The HX water is cooler than the brew temp and heats back up as it hits the group. Therefore you should add 2 degrees Celsius to the thermometer reading to get the actual brew temp.
A generic example of using of the Flush-and-Go method on my Giotto would be to flush until the thermometer reads 95 degrees C, wait around 8-10 seconds until the thermometer reads 98 degrees C and brew immediately. The temperature should land between 92-92.5 degrees throughout the shot meaning an actual brew temperature between 94-94.5 degrees C.

The Flush-and-Wait method is simpler is because the group temperature is controlled via the flush and is consistent with every shot because you are over-cooling and waiting for the correct brew temp. 

With the Flush-and-Go method the idle group temperature will be different depending on the time between shots. The idle group temp determines the flush length and necessitates a chart to obtain consistent shot temps under any circumstance.







Using the chart which might seem a little cryptic at first, you will find your idle temperature on the left side of the chart (The thermometer reading at idle) and the desired brew temperature in the top of the chart. So to achieve a brew temperature at 93.5 degrees C at an idle temp of 98 degrees C, you should flush until the thermometer reads 95.5 degrees C. Please note that the above temp readings were made on an Izzo Alex HX machine and the final brew temp might be slightly different on your machine. On my Giotto I need to add an extra 1 degree Celsius to the Desired Brew Temperature numbers to get it right.

All credits for the above article goes to Mike Ripple in Michigan, US - a Home-Barista.com user (AKA Mike01)who made all the above temperature readings on his Izzo Alex.