Coffee Cup
"Espresso! My Espresso!"
An Ongoing Internet Novelette
by Randy Glass - Copyright 2011 - All rights reserved

Coffee Cup
Preinfusion and Learning To Get The Best From My Equipment

Tuesday, August 16, 2011

      My fourth espresso machine (not including the MyPressi Twist) has brought a wondrous machine into play. Silvia, our first espresso machine, was, and still is, a nice entry-level machine. it challenged me and I learned a lot from that machine but it was hit and miss. The reality of the single-boiler class of machines is that they are just that- entry level machines. They offer marginal flexibility over the process, and as a class supply temperature and water-flow control that varies from sufficient to nonexistent.
      The Vibiemme Domobar Super that came to me next was a world above the Silvia. The (relative to Silvia) massive boiler and largest-available E-61 group with thermosyphon heating brought a level of consistency, quality, and convenience that showed Silvia for what she was: an entry level machine. Just the added ability to brew and steam without the wait between the two processes, and the automatic refill of the DS's boiler were in themselves an espresso religious experience [Arabicas 2:28].
      The arrival of the Domobar Double by Vibiemme in my home just four weeks ago has opened up a whole new world (or opened a big can of worms, depending on your point of view). This machine offers me quite a remarkable set of new features:  

  • Dual boilers separates thermal control of steam so the brew temperature is not affected.  
  • Separate brew boiler with PID-controlled stability and advanced design gives remarkable brew temperature control and, more importantly, consistency.  
  • No heat exchanger to affect brew temperature stability or control.  
  • The same wonderful, massive, E-61 group that is a key feature of the VBM machines. In this case, the manual lever model.  
  • Plumbed water supply.
          And while these (and more) are all exciting and important in regards to the quality of the espresso, it is the last two, the manual E-61 group and the plumbed water supply, that I am addressing in this chapter.
          All users take the machine they have and attempt to get the best possible from it. Over the last week or two I read about a process that I had not attempted previously because I did not have the tools to do so. This morning I was able to produce a very nice espresso which made a delicious espresso by applying that process. Let me detail what I did:
          It starts with a light roasted coffee. That tells you little because in some circles, light-roasted means a bean that is not black and oily. In this case, to be more specific, I ejected the roast after the third or fourth click of second crack. Normally I roast to about ten to fifteen seconds into second. In the future I will probably roast to a specific bean temperature before the beginning of second, but this was a first experiment. The beans got five or six days rest (lighter roasts generally benefit from longer rest periods than dark roasts).
          The grind as well as the dose was about what I had been using previously. The difference was that I used the DD's ability to preinfuse. The line pressure can be easily applied to the locked portafitler by simply lifting the group's manual lever a few degrees past where the first resistance is felt and just before closing the brew switch. Even with the machine's power switch in the off position, water will flow through the group from the plumbing's line pressure. When the machine is heated up to temperature, this inflow of water displaces the hot water in the dedicated brew boiler and so the preinfusion is done at or near brewing temperature.
          How long to preinfuse? For this test I held the preinfusion until the first drops of espresso fall into the cup. At that point the lever was fully lifted to engage the pump and begin the full-pressure extraction.
          The result was a pleasantly smooth acidity on the palate from the straight espresso and a wonderful citrus tone to the cappuccino I made.
          The reality is, of course, that not everyone will make such an investment in making espresso at home. But the point is one that has been addressed so many times before (even in the previous chapter on this very website as a matter of fact). With any given coffee and quality water, any talented barista can get the best from their equipment. But the equipment is the limiting factor and the performance of the equipment can only create espresso of a given quality and no more. Quite the opposite, you, as a barista, can change. You can take courses, read forums, ask questions, research websites such as mine (if I may be so bold), change your process, adapt to the coffee, and so forth.
          As an organism you can adapt to your environment and I urge you to do so. Try different coffees, grind finer and dose less, grind more coarsely and dose a bit more. Don't get stuck in a rut by doing things the same way just because it's how you have been doing things. Your espresso equipment is what it is. So while it is up to you to get the best you can from your equipment, before buying an espresso machine and grinder, carefully consider your commitment to this endeavor and your level of desire to get the best possible espresso at home. The equipment does matter.

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