HomeRoast Digest


Topic: Boiler maintainence (17 msgs / 391 lines)
1) From: Barry Luterman
This is a multi-part message in MIME format.
This came up on another list I am on. Don't remember it being on this =
list but even if it has it bears repeating.
A way to control the total dissolved solids in the boiler is once a week =
when the machine is up to operating temperature. Shut the machine off =
and draw off a cup of hot water from the hot water valve. Turn the =
machine back on the water will refill from the reservoir.The refilled =
water will contain less total dissolved solids. If you get in the habit =
of doing this once a week, probably the same time you clean with Cafiza, =
there will be a longer time between major de-scaling for your machine.

2) From: Leo Zick
This is a multi-part message in MIME format.
why will the refilled water have less TDS?
why does the machine have to be off to do this? i can draw a cup off and the
refill will kick in around 6oz through.
 
ive also stopped cafiza-ing weekly, or bi-weekly.  i detergent backflush
about once a month now. 
with water backflushes and wiggles and toothbrush wipes after each shot, ive
removed the screen and all is quite clean. ive also disassembled the top and
bottom pieces of the grouphead to check this - i dont think detergent
backflusing that often is a good thing, esp since it removes so much oil
from the handle/spring assembly.  
From: Barry Luterman [mailto:lutermanb001] 
Sent: Tuesday, October 03, 2006 9:31 PM
To: homeroast
Subject: +Boiler maintainence
This came up on another list I am on. Don't remember it being on this list
but even if it has it bears repeating.
A way to control the total dissolved solids in the boiler is once a week
when the machine is up to operating temperature. Shut the machine off and
draw off a cup of hot water from the hot water valve. Turn the machine back
on the water will refill from the reservoir.The refilled water will contain
less total dissolved solids. If you get in the habit of doing this once a
week, probably the same time you clean with Cafiza, there will be a longer
time between major de-scaling for your machine.

3) From: Justin Marquez
On 10/3/06, Barry Luterman  wrote:
<Snip>
Barry - The standard thing operators of steam boilers (and cooling
towers) do is to have a small stream being removed all the time,
called the blowdown, to help keep the water in the system more diluted
of TDS.  The reason is that in both of them, water is evaporated out
as a part of the process and the water left behind has more dissolved
solids. This builds with time as the makeup water is added. (It is a
serious problem in industrial steam systems, since the solids plug up
the boiler tubes.)
In the boiler in an espresso machine, what is removed from the boiler
to make a shot is not steam as much as it is hot water, so the buildup
of TDS would not be expected as much as in a steam boiler.
I am not sure how the milk steamer wand works... does it draw real
steam off the top of the boiler, or does it draw water heated above
normal boiling point conditions so that steam is produced when the
wand is used and the hot water flashed? If it draws real steam, then
that is a  likely source of  TDS buildup.  Local hot spots on the
heating element will likely get solids plated out.
Safe Journeys and Sweet Music
Justin Marquez (CYPRESS, TX)

4) From: miKe mcKoffee
TDS build-up is not a issue in single boiler dual use machines like Silvia
where the brew water is the boiler water. HX machines and dual boiler
machines whole 'nother matter. HX machine boiler TDS build-up is an issue
with the shot water coming through the HX plumbing not from the boiler. Dual
boiler machine it's only the steam boiler with TDS build-up issue.
Steam wand steam comes from steam which mean above boiling boiler yes.
"Real" steam? Is there such a thing as faux steam!-)
Kona Konnaisseur miKe mcKoffee
URL to Rosto mods, FrankenFormer, some recipes etc:http://mdmint.home.comcast.net/coffee/Rosto_mod.htmUltimately the quest for Koffee Nirvana is a solitary path. To know I must
first not know. And in knowing know I know not. Each Personal enlightenment
found exploring the many divergent foot steps of Those who have gone before.
<Snip>

5) From: miKe mcKoffee
<Snip>
[mailto:homeroast-admin] On Behalf Of Leo Zick
<Snip>
	
<Snip>
Fresh water versus water left after steaming removes pure H2O leaving TDS
behind.
<Snip>
It doesn't on most HX machines. DB Brewtus it has to be.
<Snip>
Drawing in only a cup will help but that's a small percentage of most
prosumer espresso machine capacity.
<Snip>
backflush about once a month now. 
	with water backflushes and wiggles and toothbrush wipes after each
shot, ive removed the screen and all is quite clean. ive also disassembled
the top and bottom pieces of the grouphead to check this - i dont think
detergent backflusing that often is a good thing, esp since it removes so
much oil from the handle/spring assembly.
<Snip>
Left behind coffee oils go rancid much sooner than a month, whether from a
few shots or hundreds of shots doesn't matter. I'll stick with minimum
weekly detergent backflushes and put up with sqeaky lever for a shot or two
after each backflush. Most (actually all I've ever talked to either in
person or via 'Net) espresso professionals agree a clean machine is mucho
important to quality shots. Quality oriented cafes detergent backflush
multiple times a day! Water only backflushing does not remove all coffee
oils. Try this: pull a shot into a clear demi. Drink it. Let empty demi sit
a couple hours. Now rinse it out with boiling water (do not wipe it out in
anyway.) After it drys compare it to a clean clear demi. Are they
identically clear? NO! Coffee oils remain same as a group. And toothbrush
and water only won't get the entire brew path. Plus PF and basket need to be
regularly espresso cleaner detergent cleaned too. But hey, it's your machine
and your shots going into your cups!
Kona Konnaisseur miKe mcKoffee
URL to Rosto mods, FrankenFormer, some recipes etc:http://mdmint.home.comcast.net/coffee/Rosto_mod.htmUltimately the quest for Koffee Nirvana is a solitary path. To know I must
first not know. And in knowing know I know not. Each Personal enlightenment
found exploring the many divergent foot steps of Those who have gone before.

6) From: Michael Dhabolt
Another way of dealing with the 'brine' left in the boiler (HX
machine) from steam use, is to drain and flush the boiler on a regular
basis.  I added a little copper tubing and a valve to the boiler drain
fitting on my Astoria.  About once a month I install a length of tygon
tubing to the valve and drain the boiler into the sink (machine off),
refill the boiler and drain it again, refill the boiler and turn the
machine on - - good for a month.  The brine after a month of three or
four frothed milk drinks a day will peg my TDS meter.
Mike (just plain)

7) From: Leo Zick
Mike:
Why would the HX line be subject to more TDS than the boiler?  except  
when idling, it has a constant flow of water through it, much like  
city water through residential piping.  plus, with the addition of  
heat, id assume this helps even more in keeping the tube insides clean.
Justin was correct in his 'real' steam analogy.  flashed steam isnt as  
'pure' b/c it can tend to still have some wetness in it..
Quoting miKe mcKoffee :
<Snip>
al
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t
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e.
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8) From: Justin Marquez
On 10/3/06, miKe mcKoffee  wrote:
<Snip>
"Real steam" is 100% water vapor at (saturated steam) or above
(superheated steam) the temperature of vaporization at the system
pressure.
Steam also comes in a variety of "quality" conditions.  The typical
steam coming from the spout of a tea kettle has both water vapor and a
mist of water droplets. The percent quality of steam is a measure of
the portion of "real steam" in the mix. I.e., 70% quality steam has
70% by weight of water vapor and 30% hot water droplets. "If you can
see the stream, it ain't all steam."
The reason this is important industrially is that steam heats stuff by
giving up it's latent heat of vaporization as it condenses. Steam of
50% "quality" has only half of the latent heat available as that of
100% (saturated) steam. The latent heat is nearly 1000 times greater
than the sensible heat from just cooling hot water.
If you have a system at elevated pressure heated to produce saturated
steam and you withdraw the water from the lower part of the boiler,
then flash that thru a valve - you will produce some steam as the
pressure is reduced at the valve. There will also be some hot water
which does not vaporize as the flashing process cools the mixture a
bit as well. You end up with a mixture of "real steam" at atmoshpheric
pressure and some hot water. The ratio of steam to hot water produced
depends on the pressure and temperature of the hot water drawn from
the bottom of the boiler.
Safe Journeys and Sweet Music
Justin Marquez (CYPRESS, TX)

9) From: Leo Zick
the only time TDS would have a chance to build up is through use of  
the steam wand, right?  thats why i questioned the OP.  the only other  
thing i see happening is scale buildup inside the boiler from the  
water sitting in the same place.  even that should be relative as some  
water will always evaporate (evidenced by the machine filling the  
boiler every so often on its own) from evaporation of the water/steam  
combo via heat transfer, i presume.  id guess if you never steam or  
use hot water, you could fill the tank with distilled water and be  
less worried.
personally, i use both hot water (despite the fact its not truly  
boiling, i still use it for my tea, and hot chocolate, etc) and the  
steam wand, so i try to drain a cup or 2 of water every 1-2 days to  
prevent a scale line from occuring.  drawing almost any amount of  
water should be enough as the movement prevents the water from  
creating a scale line in the tank.  as far as TDS, it probably wouldnt  
hurt to drain the boiler every so often (which i also do), but again,  
i cant see a whole lot building up, esp if the water is filtered.
i will admit the machine seemed to run more 'effectively' after  
descaling it, but that could have been the old butt-dyno measurement.  
(ie, not accurate)
re: detergent, i reduced the frequency b/c i monitor the brew path and  
its components. ill go home tonight (assuming i remember) and take a  
picture of the inside of my grouphead and screen and show you.  i do  
clean the baskets, etc. i pretty much only use a naked pf, so  
'cleaning' that isnt as critical.  i will admit i dont like having the  
PFs sit in the detergent as it leaves a 'metallic' taste and smell on  
their insides, so i mostly hot water rinse them too. ill take a pic of  
them to show you their 'cleanliness' as well.
are we allowed to attach pics to these emails?  if not, ill make a  
post on H-B.
Quoting miKe mcKoffee :
<Snip>
o
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t
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be
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ne
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t
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e.
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10) From: Leo Zick
mechanical or industrial engineer?
:)
Leo (mechE)
Quoting Justin Marquez :
<Snip>

11) From: Leo Zick
do you only use the steam wand, never the hot water?
id imagine that if you drain or use some water from the boiler  
frequently, the TDS would be lower.  have you experienced this?
if not, do you think you could empty a cup of water every day for a  
week, then measure the TDS of the syphoned water? im curious to see  
the difference..
Quoting Michael Dhabolt :
<Snip>

12) From: miKe mcKoffee
I said HX machine boiler TDS build-up is an issue, didn't say the HX line
was. Read what I posted below again. Though could have been a bit unclear
when I said ..."with" the shot water coming from... maybe should have said
..."because" the shot water coming from.
miKe
<Snip>

13) From: Leo Zick
"HX machine boiler TDS build-up is an issue with the shot water coming  
through the HX plumbing not from the boiler."
that interprets to me as "the hx plumbing is the problem, not the boiler".
BTW, why wouldnt there be concern for TDS on the brew water of a dual  
boiler machine?  does the brew boiler simply heat and extract water  
continuously? id imagine, though, if you left your machine on for the  
weekend or so, thats an opportunity for a scale line to form, right?
Quoting miKe mcKoffee :
<Snip>

14) From: Justin Marquez
On 10/4/06, Leo Zick  wrote:
<Snip>
Chemical engineer, working in the "awl & gas bidniz".
Safe Journeys and Sweet Music
Justin Marquez (CYPRESS, TX)

15) From: miKe mcKoffee
<Snip>
A DB machine the brew boiler water is the shot water and refreshed anytime
water pulled through group so greater than normal disolved solids not an
issue. Scale formation and TDS two different issues. (Of course higher TDS
also forms scale faster.) DB machine with large brew boiler in low shot
volume setting "may" have a different issue, brew boiler water possibly
getting stale. 
Kona Konnaisseur miKe mcKoffee
URL to Rosto mods, FrankenFormer, some recipes etc:http://mdmint.home.comcast.net/coffee/Rosto_mod.htmUltimately the quest for Koffee Nirvana is a solitary path. To know I must
first not know. And in knowing know I know not. Each Personal enlightenment
found exploring the many divergent foot steps of Those who have gone before.

16) From: Leo Zick
ohh, one of the really smart ones :o
Quoting Justin Marquez :
<Snip>

17) From: miKe mcKoffee
<Snip>
Adding distilled water to the boiler on an HX machine a great way to lower
TDS and greatly reduce scaling. Easy on a tank model, a PIA on direct
connect! Steaming is major cause of high TDS steam boiler. Using hotwater
wand on most prosumer HX machines for Americanos or Tea or hot chocolate
highly beneficial in keeping boiler water TDS low, same as simply flushing.
(some HX machines don't draw hot water from the boiler but HX or themoblock
it) 
 
<Snip>
What can be seen by the naked eye on metal versus what is actually there may
not be the same. Hence the clear shot glass test. As far as metallic taste
after detergent backflushing that's why a seasoning shot is pulled after
detergent backflushing. FWIW when detergent backflushing good time to quick
clean grinder with Minute Rice or Grindz. Then use the final grinder bean
flush for the seasoning shot... 
Kona Konnaisseur miKe mcKoffee
URL to Rosto mods, FrankenFormer, some recipes etc:http://mdmint.home.comcast.net/coffee/Rosto_mod.htmUltimately the quest for Koffee Nirvana is a solitary path. To know I must
first not know. And in knowing know I know not. Each Personal enlightenment
found exploring the many divergent foot steps of Those who have gone before.


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