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Thread: Back Flushing

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    Back Flushing

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    Hi

    Do any of you back flush if so how often?

    Rich

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    Re: Back Flushing

    Gee I have heard so many differing opinions on this Richard. We use Mr Boema once a month, and back flush with just normal water etc on Sunday evening, but only a mild backflush, I think if you clean as you go, wipe wipe wipe, a lot of your back flushing would depend on how much brew you put through it wouldnt it?

    One thing we do though is to remove the shower screem often and give it a good scrubb too.

    FB

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    Re: Back Flushing

    Hi,

    I generally make between 3 and 6 coffees per day with peaks of up to maybe a dozen or more when visitors come over and have got into the habit of back-flushing Mokita about once per fortnight using "Espresso Clean" that I bought from Coffee Parts.

    Use a very gentle technique so as not to run the risk of blowing or weakening any high pressure joints. Probably takes a bit longer than for someone who has an all copper piped machine but one thing Ive got plenty of, and thats time.

    Cheers,
    Dimal.

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    Re: Back Flushing


    Rich
    There are two types of back flush or head cleaning.
    1. Clear water
    2. Chemical

    If your machine is able to be back flushed, then, I strongly recommend a clean water blind filter backflush after each use, ie when you finish for the day. Does not matter how many coffees you make each day. If it is not back flushed you might accumulate some rancid oils etc, in the group head.
    If you do a clear water back flush after finishing each day then I can assure you that the next espresso will be totally different than if you dont do the back flush.
    Then once a week ie after the Sunday morning ritual, do a mild chemical back flush.
    Try it!!!! ;D
    JD

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    Re: Back Flushing

    I do actually back flush it was a question to get a thread going ;)

    Rich

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    Re: Back Flushing

    JD even many of the commercial barristas recomend not to use the chemical option too much, For a home enviroment where you only shoot upto 15 shots for a day a simple flush of your Grouphead is all that is required, Once a week do a non chemical flush....

    Every time you use the Chemical option there is a taste left behind, and basically its a major overkill, the use of the blind filter to flush often is a good idea, but to use the chemical option once a week I think is a bit much, in a commercial enviroment once a week might be justified.

    But thas only my thoughts and what I have been taught, I may be entirely wrong.

    FB

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    Re: Back Flushing

    Rich
    OK. A great and controversial topic.
    Back flushing is an interesting subject, often misunderstood, avoided or put into the tooooo hard basket by many. It is an essential part of keeping the espresso machine clean and helps stop any potential build-up of rancid oils on the parts that come into contact with the coffee oils.

    FB
    I wont say you are right or wrong. I was just expressing my opinion as to what I believe is the best way of keeping your equipment in top condition. I regularly taste new blends and different coffees. I taste via an espresso, ristretto or doppio ristretto. My preferred poison is a piccolo latte made from the first 20 ml out of an 18 odd gram double filter basket.

    The clean machine, in a bit more detail:
    I believe that it doesnt matter how many shots you pull in a day or a session. The clear water back flush:
    1. will reduce the "grunge" build-up
    2. make the chemical clean easier and quicker
    3. significantly improve the taste of the next espresso
    4. add longevity to the machine.

    Each time the machine is used the coffee oils will start to build up. These coffee oils are then subjected to heat everytime the machine is turned on. These oils start to burn, become rancid and will definitely impart unwanted and undesirable tastes into the espresso. Often some of these tastes go un-noticed in milk-based coffees, but to a person with a trained palate, they can usually be picked up.
    Whether I make one coffee or ten during a session, when finished, I always:
    1. flush the group head
    2. give the seal a brush
    3. clean water back flush group head
    4. rinse the group handle and filter basket in hot water

    Then once a week (home environment) I always do a chemical clean of the machine and group handle. On the E61 heads I regularly pull out the shower screens and check for any build-up of oils etc. To date on account of following my cleaning regine, the build-up has been negligable. On the regular head machine I had, I religously dropped the shower screen each week and scrubbed it. Then followed with a chemical clean.

    I do not believe the above is over doing it. If you are an espresso or ristretto drinker, then, doing the above will make a marked difference in your next coffee.

    With regard to the tastes from the cleaning detergent, easy to sort out. After the chemical clean and just before you pull your next shot, "SEASON" the machine. Simply make 2-3 shots and toss out, before making one to drink. Yep you do tend to waste a few grams of coffee here and there, but it is worth it. Also when you do these seasoning shots, it is an opportunity to check the extraction rate and make a change to the grind, if necessary.

    The commercial environment is another ball game. I wont go into detail.
    But suffice to say, in any commercial environment as a minimum:
    1. the group handles rinsed every few hours
    2. the machine regularly back flushed thoughtout the day
    3. a full chemical clean at the end of the day.
    JD



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    Re: Back Flushing

    Quote Originally Posted by CoffeeMugs link=1097923570/0#4 date=1100175586
    I do actually back flush it was a question to get a thread going ;)

    Rich
    Rich, I thought you were a member of the antibackflush league based on Rancilios recommendations for Silvia.

    Have you been converted?

    I chemical backflush once a month or so, usually around the time I descale with citric acid.(though not at the same time!)

    Water flushing every second day or when Im not rushed in the morning I will try and do it daily.

    I just picked up a la Cimbali machine which looks like its never been backflushed, ever! Years of accumulated grounds are almost superglued to the shower screen. No wonder the people wanted to get rid of it, the coffee must have tasted competely vile.

    Apart from taste issues I understood backflushing was an important preventative maintenance procedure for the threeway valve.

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    Re: Back Flushing

    I possibly should have qualified my comments on back flushing, they are geared to commercial style machines eg Giotto, Diadema etc.
    JD

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    Re: Back Flushing

    I back flush my Giotto with water and a blind filter a couple of times a week.

    Coffee machine detergent is used maybe every month or so. The water back flush reduces the need to put chemicals through your machine as regularly IMHO.

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    Re: Back Flushing

    While new to the whole high-end world of espresso equipment in order to make every pull as good and as clean as possible I backflush Cimba with water and clean the grouphead with a brush after every pull repeating as many times as needed until theres no signs of grounds left behind on the gasket or screen. I then do a chemical flush once a week with an environmentally friendly agent as well as soaking the shower screens and portafilters in it. Additionally I drain and flush my whole system once a week or after one day of non-use.

    I normally do about 15 pulls a day with the most Ive ever done in a single day so far being about 60 or 70.

    Java "You wont get a God Shot with a dirty machine" phile

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    Re: Back Flushing

    micstone - What you are doing is certainly giving the screen and the group seal a good flush but that isnt really backflushing as it doesnt build any pressure in the group.

    Javaphile - I cant believe the discipline you are following, you would do Schomer proud! :D It would certainly put a hell of a lot of water through the machine.

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    Re: Back Flushing

    Quote Originally Posted by Wired link=1097923570/0#12 date=1103750676
    micstone -
    Javaphile - I cant believe the discipline you are following, you would do Schomer proud! :D It would certainly put a hell of a lot of water through the machine.
    I had a laugh For me putting additional water through the machine is actually a good thing. My baby is a 2-head commercial unit with an 11l boiler. With just me in the house it doesnt have mush water put though it with just pulling shots. If I didnt do all the extra flushing the water would quickly go stale and ruin the espresso. :)

    Java "Stale water is baaaaad" phile

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    Re: Back Flushing

    Fellas,

    to save confusion with those of you that have domestic, as opposed to commercial machines.

    a) it is an accepted part of the daily management routine of a commercial cafe enterprise to use the blind filter to "overflow" water around the group/shower area. This removes grinds that would otherwise build up and clog the "group ring" area (ie the area where you fit the group handle / filter holder up to). Immediately after this, use a group brush to run around up in the group seal / ring area to dislodge persistent grinds, then overflow more water with the blind filter fitted again to get it all out. After having done this, you backflush the group/solenoid.

    b) it is also an accepted part of the daily management routine of a commercial cafe enterprise to run say, a litre or two (or whatever) of water out of the boiler every day (or even several times a day) to get some movement of fresh water into what would otherwise become very stale...

    In addition, "accepted practice" to some, means nothing to others, particularly those that have no formal training in or understanding of the proper management of commercial espresso coffee machines....!

    And just to set the record straight, point b) above is for COMMERCIAL design machines ie, those with heat exchangers, and the operator is "freshening" up BOILER water, which is NOT the water used to make coffee in these machines. Owners of domestic machines need not therefore take any notice of this. They should also note there is no point in trying to "backflush" domestic machines not fitted with a group electrovalve or solenoid, which is around 98 percent of all domestic machines.

    ***

    The act of "temperature surfing" or "purging" the groups before fitting the group handle to make coffee, should in most cases be sufficient to "freshen" that water that will be used to brew coffee, which of course in a commercial machine is not boiler water and comes directly from the "mains" (or an internal water reservoir/tank in the event of semi-commercial machines not having a mains water connection). Purging / temperature surfing before brewing is plenty enough to freshen up the water in a domestic machine.

    Hope this helps.

    Regardez,
    FC.

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    Re: Back Flushing

    As my silvia is now out of warranty I backflush. Every time I do I get all sorts of icky crap comming out. Plus If I bust it i can fix it :)

    The Rancilio Importer definately doesnt reccomend back flushing he even told me Silvias dont need descaling. I got the impression as far as he was concerned if you backflush a Silvia. Kiss goodbye to your warranty.

    So I voided my warranty months ago.

    Rich

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    Re: Back Flushing

    Quote Originally Posted by Fresh_Coffee link=1097923570/0#14 date=1103792093

    And just to set the record straight, point b) above is for COMMERCIAL design machines ie, those with heat exchangers, and the operator is "freshening" up BOILER water, which is NOT the water used to make coffee in these machines.
    Hey FC,

    I guess Im unclear by what you mean by the above quote as my Cimbali M28 only has the one boiler and all water used on it goes through the boiler. Including that used for pulling shots.

    Java "Flush baby, flush!" phile

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    Re: Back Flushing

    Java,

    it is more likely than not that your commercial M28 machine has heat exchangers. This means the BREWING water passes through the boiler, *but NOT into and out of the boiler water. The brew water is INSIDE separate piping called heat exchangers. The steam and stale boiling water in the boiler, which is so to speak "wrapped around" the heat exchanger pipes, causes the fresh "cool" water inside the heat exchanger pipe to heat up...ergo "heat exchangers". This water inside the heat exchangers comes direct from your mains water connection and is that which is pumped through the coffee grounds in the filter ,to produce espresso. Coffee is made with fresh water, the rest of the water/steam coming from your (anyones) commercial machine is stale.

    The purpose of the water (which becomes stale & de-oxigenated) in the boiler is to create steam, and to cause the exchange of heat into the fresh water coming through the heat exchangers. So there are 2 separate water systems happening inside the boiler, and they do not mix.

    Ergo, the explanation a couple of posts up re the separate flushing of boiler water and brew water in commercial machines.

    ***************

    Rich,

    as has already been noted in earlier parts of this topic the backflushing of DOMESTIC machines fitted with group solenoids is a bone of contention, and it begs a more technical discussion of what backflushing actually does.

    So for others in the forum that are not familiar with what happens with backflushing, it goes something like this:

    Brewing water passes through the boiler, into the group (heating up the group along the way) and into the groups electrovalve. The electrovalve is nothing more than an electric tap and it does not allow the passage of water back through the group and the coffee grounds until it is energised when the operator pushes the brew button on the mahcine. When it is energised, the valve opens and allows brewing water to pass through the group and produce espresso.

    So far, all of this is clean water.

    When the operator is finished brewing and the brew button is pressed off, the in line water pump PRESSURE that was pushing clean water in the direction of the group handle / filter holder has the opportunity to take the path of least resistance, which is to flow backwards agains the spring tension of the now de energised electrovalve, and "exhaust" the pressure (from the group) backwards into the drip tray...and this way you can remove the group handle from the machine without having it "explode" or pop off and put a heap of extremely hot water on your hand/wrist!

    What all this means, is that every time you make coffee, you have a flow of clean water through the electrovalve and group, and at the end of each coffee brewing "cycle" you have a corresponding "exhaust" or "pressure relief" of brewed coffee back through the group and electrovalve.

    In real terms then, you are flushing clean water through the electrovalve and group every time you brew coffee, or simply flow or purge water through the group. If an operator removes and cleans the group shower at regular intervals, most (but not all) of the garbage that solidifies out of the wet coffee brew to clog up the system, is cleaned out.

    Whilst backflushng with (approved) coffee machine detergent cleans out the shower, water passage and electrovalve without the need to remove anything, its primary function in the maintenance of an espresso machine is to lessen the possibility of the electrovalve becoming CLOGGED up with oily deposits over time and ceasing to function, whereby the operator can end up with burns to hand and wrist when removing the group handle, from the lack of pressure relief at the end of each brew cycle....and ofcourse, it lessens the possibility of introducing "off flavours" into your brew from any deposits of oily crud that can build up over time.

    If you watch the pressure relief into the drip tray, you will see that clean water is relieved / exhausted even when you siomply flow water through the group...ie, you dont need to use a blind fiilter tpo get some clean water flowing back through the electrovalve... but of course if you wish to use detergent to backflush with, you have to use a blind filter!

    Neither Rancilio nor Gaggia provide a blind filter with their "electrovalve grouped" domestic machines...

    The never ending discussion, with many interpretations !!!

    Regardez,
    FC.
    PS again for the benefit forum readers perplexed by all this....if your domestic espresso machine is not fitted with a group electrovalve or solenoid valve (MOST domestics), all of this is academic as you can only backflush solenoid / electrovalve operated groups.

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    Re: Back Flushing

    Quote Originally Posted by Javaphile link=1097923570/15#16 date=1103823557

    Hey FC,

    I guess Im unclear by what you mean by the above quote as my Cimbali M28 only has the one boiler and all water used on it goes through the boiler. *Including that used for pulling shots.

    Java "Flush baby, flush!" phile
    Hi Java,

    did you end up pulling your cimbali right down and removing the HX from the boiler? The water path will become pretty evident once you have the pieces in front of you. As FC said the boiler steam/water is used to heat the shot water in the HX. The interior of my hx was pretty grotty and Im glad I cleaned it out.

    Some machines have the hx welded to the boiler and if the hx is damaged by freezing or whatever you basically throw the machine away, the cimbali hx fortunately is a seperate part which can be easily removed and replaced.

    Owen Egan has a good visual diary of what can go wrong with a hx check it out at http://owenegan.com/pix/espresso/cimbuini

  19. #19
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    Re: Back Flushing

    Behmor Brazen - $249 - Free Freight
    oooOOOOOOoooOOOoo <Lightening flashes and strikes Javaphile and the lightbulb over his head goes on> Ive been laboring under a false assumption! Ive been assumming that the HXs are being fed with boiler water! <MANY things suddenly start to make sense!> Thanks FC!!!

    Yes mauricem I did actually tear my Cimbali all the way down. And I do mean *all the way down. By the time I was done there was nothing left on the frame but the electrical harness. :) However, it was not being torn down trying to find some problem. Rather it was a complete tear-down, cleaning/descaling, and rebuilding. Starting with a working unit.

    This was my first ever espresso machine (Ive owned several small pump units that claimed the name but werent) and when I finally got it after 3 years of back and forth between its now former owner and myself the only problem that prevented it from being used (and which the previouos owner had been attempting to fix for those same 3 years) was a leak. A leak I diagnosed and fixed less than 5 minutes after my friend and I had lugged the monster in and dropped it on my kitchen counter. I had a laugh

    After Id fixed its only problem I then decided to tear it all apart, clean it, and put it back together as good as new. I followed the water paths and while there were a couple of questionable areas I *thought* I had them all figured out until FC threw a wrench into that! Knowing now that the HXs are being supplied with fresh water rather than boiler water I now know that the valves work a bit different than I had assumed (based on boiler water being fed to the HXs).

    A couple of head itches have now been cured thanks to this info! Such as why the steamed milk would taste of stale water but not the espresso. And why the temp of the water coming out of the head could drop so much if you ran a lot through it. And like why there was that other valve there when it really didnt appear to be needed! Nice!

    Goes to show what happens when one makes ASSumptions!

    Java "*pets* his newly lit over-head lightbulb" phile



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