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  • Question time!

    Hey all!

    So Im very much still learning, but Im definitely getting there. At the moment, I figure itd help if I asked a few questions.

    First of all, Ive heard (and read) the term blonding thrown around a lot, but to be perfectly honest Im not altogether sure what it means. At what point should I be stopping the coffee coming out? Is there a technical term for that particular process? Pictures might help.

    Secondly, I got some new coffee early this morning (Way too early for me to be awake, IMHO). I noticed that, compared with the coffee I got from Veneziano, this one seemed to require a much finer grind, since when I used it in the same setup, the flow rate seemed way too high, and it tasted... bad. So my question is, will I find I need to change the setting with each different coffee?

    Oh and - flow rate! What sort of flow rate am I looking for? I think I read 25ml in 30 seconds, or something like that? I assume its not good for the machine to attempt to use something thats way too fine or excessively tamped...

    Cleaning! I got a nice little container that says cleaning powder. I can use it to clean my machine, I guess, since it says Clean Machine.... so.... yeah... Im not sure how this interacts with my machine. Some kind of ritual dance, perhaps?

    I know I had more but they seem to have evaporated from my mind - maybe later.

  • #2
    Re: Question time!

    Good questions Philbert.

    Blonding: This is when the coffee changes from a dark hazelnut colour to more of a yellow which is when the more bitter elements come out. Since blonding normally starts through the overextraction of one part of the puck, it normally initially appears as a light streak in otherwise darker espresso which is normally the time to stop the shot if youre after a richer sweeter ristretto rather than espresso; however that can sometimes be hard to see depending on how your portafilter spouts are designed and how well lit your espresso area is. As the overextraction continues this blondness eventually takes completely over and the whole espresso coming out get paler and paler yellow until its translucent. If your flow rate is too fast it can be very hard to pick this transition point as it happens very quickly and you hardly get any dark properly extracted espresso; alternatively if the flow is too slow you may not get much crema so blonding simply becomes a paling of whatevers coming out. So you need a good extraction to start with to be able to pick this point more easily. Ill try to remember to take some pics next time I do a shot (just finished actually! )

    Grind: Yep different beans need different grind, and even on the same bean the right grind changes with age of beans, temperature and humidity, all other things being equal. Thats why its so important to have your own grinder so you can make these fine adjustments yourself, quite apart from the overwhelming freshness argument. There is such thing as espresso grind but its a very approximate thing which varies in its detail.

    Flow rate: should be about 30ml per shot in 25 seconds nominally. So if youre using a double basket, thats 60ml in 25 secs. But thats really *about* the speed of extraction youre after (some beans need a slightly coarser or finer grind to present their best), as above you may prefer to stop it before the full 60ml is extracted to limit your drink to the sweeter components. I find with the Silvia theres about 6 seconds from when I hit the brew switch to when espresso starts coming out

    Cleaning powder: Its probably backflushing detergent, which you stick into a blind filter (filter basket with no holes), load as you normally would to make a coffee and run the brew cycle for a few seconds. This dissolves the detergent and escapes through the 3-way valve, cleaning the group area on its way out. There are good descriptions on the web and here on CS about how to do it. However the powder *may* be descaling powder in which case its for a totally different purpose. If it looks coarse like washing powder its backflushing detergent, if it looks like fine white sugar its probably descaling powder.

    HTH,
    Greg

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    • #3
      Re: Question time!

      Ive put a couple of videos up for you to compare.

      Fast extraction where blonding point is harder to pick exactly:
      http://www.youtube.com/watch?v=90i0cibwdNY

      Slow extraction (OK old beans!) but onset of blonding more obvious. The first streak of blonding is about the 14 second mark:
      http://www.youtube.com/watch?v=FxXtDtKruaA

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      • #4
        Re: Question time!

        Originally posted by Greg Pullman link=1201236419/0#1 date=1201244463
        Cleaning powder: Its probably backflushing detergent, which you stick into a blind filter (filter basket with no holes), load as you normally would to make a coffee and run the brew cycle for a few seconds. This dissolves the detergent and escapes through the 3-way valve, cleaning the group area on its way out. There are good descriptions on the web and here on CS about how to do it. However the powder *may* be descaling powder in which case its for a totally different purpose. If it looks coarse like washing powder its backflushing detergent, if it looks like fine white sugar its probably descaling powder.
        Ill just add to what Greg said. Cleaning powder, ie. backflushing detergent, is also used for cleaning the portafilter, filter baskets, showerscreen, etc. Just dissolve it in hot water and soak the parts in it.


        Bill

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        • #5
          Re: Question time!

          That is a very interesting extraction, Greg. The coffee is jet black for a second or so and then immediately turns colour. Very interesting.

          By the way, I stumbled across this one:

          http://au.youtube.com/watch?v=5mapl0Fw-_M&NR=1

          Talk about turgind. The guy keeps flushing his Silvia like it is some HX machine --several times. Loading the portafilter takes forever. Must be about 50 clicks of the doser.... then spinning the tamper several times to polish (not sure any polishing is necessary)...

          By the time hes finished the portafilter would be stone cold, the group head ditto from all the flushes....

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          • #6
            Re: Question time!

            Yep they were the end of some beans I roasted a few weeks ago and figured I may as well get some use out of them. Just about to roast some more but theyll need to rest a few days yet before theyre ready for something like this.

            Interesting that one you linked to. It looks like hes trying to temp surf; the first couple of flushes he did until the heater light came on and then he stopped which is what makes me think that, but then the ones he did before loading the pf didnt seem to have any correlation to the light as it stayed off the whole time :-? I must say Ive seen worse techniques though - he did at least settle the grinds in the portafilter and smooth them off before tamping, but youre right its a slow preparation and he would have gotten a nice fracture through the puck with that hefty whack before doing the monster tamp. Not to mention the fact you can almost see through the espresso stream by the time he stops the shot!

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            • #7
              Re: Question time!

              I almost fell asleep watching that guys technique!!

              Comment


              • #8
                Re: Question time!

                Unfortunately, posts like that -- probably meant to be instructive -- have a negative effect on impressionable minds (and isnt that all of us seeking knowledge). We web surf gleaning information, and come across that post.

                If we did not know any better, we would assume that THAT is the way its done. After all, the home-barista has gone to the trouble of posting his technique --wouldnt do that if it was wrong, would he?

                And he appears to be meticulous, going to all the great lengths. Only someone out to make a superior coffee would do that, would he not? And on it goes....

                Comment


                • #9
                  Re: Question time!

                  Huh? What? Sorry, mustve drifted off... the last thing I remember was that guy flushing his machine for the third time, then I guess I fell asleep or something.

                  Seriously though Im guessing hes not a good role model for knowing when to stop shots. Which brings me to a follow up question. Now that I have a rough idea of the concept of blonding, what is generally accepted as the good time relative to blonding to stop a shot? Im assuming its a matter of taste, so Ill say, when would *you* stop a shot?

                  Also, in case its a. relevant, and b. unknown to you, Ill say Im using a VBM Levetta and a ECM KS grinder.

                  Id try some shots now but people are trying to tell me about something called sleep... you know anything about that?

                  Phill

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                  • #10
                    Re: Question time!

                    Sleep is for the decaffeinated!

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                    • #11
                      Re: Question time!

                      The longer the better. With that slow shot I would have pulled it about the 14 second from the start of the video (8 seconds from the start of the pump) which would have only given about 10ml of espresso. But thats old beans for you which is why you need to understand what youre trying to achieve so you can get the best result from whatever comes out (and of course get fresh beans in the first place! :. Fresh beans properly ground and at the right age, with all other factors right and you might get a 15 seconds from the start of the pump, maybe even 20, or maybe 10. It just depends, including on bean type and roast.

                      To put this in perspective, Epic are fairly well respected as far as their espresso capabilities. Even in that environment with beans exactly at their peak, a PIDd Synesso on 24/7 and beans ground with a Mazzer Robur just before grinding, youd still get variations in extraction time. All the shots were exceptional, but you may still have a 2-3 second difference from when youd need to stop the shot, sometimes a bit more.

                      Greg

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