
How tinkerers brought PID temp control to espresso machines - troydavis
http://home.lamarzoccousa.com/history-of-the-pid/
======
nicpottier
I was in Vivace's the other day and Schomer's latest quest seems to be around
water. As I understand it they are starting from purified water then adding in
their own blend of minerals to achieve the consistency they want. (apparently
only the Capitol Hill location is testing this, more here:
[http://espressovivace.com/index.php/water-
formulation/](http://espressovivace.com/index.php/water-formulation/))

I have a PID'd Silvia ([https://www.seattlecoffeegear.com/pid-retrofit-kit-
for-ranci...](https://www.seattlecoffeegear.com/pid-retrofit-kit-for-rancilio-
silvia-with-pre-infusion-white)) and it does make a difference. But man, the
black hole that is making repeatable excellent espresso at home doesn't end
there. You start wondering about your tamp pressure, need a $700 grinder to
have consistent adjustable grinds and start roasting your own coffee.

It is an expensive hobby, but a tasty one at least.

If you pass through Seattle, make sure to drop by Vivace, they define what
proper espresso is.

~~~
sp332
How is a $700 grinder better than any burr grinder?

~~~
Retric
Ego.

PS: Most people fail blind taste tests with this stuff. But, just like the
high end audio market spending money on junk makes some people feel good.

~~~
nicpottier
Source please?

It isn't an ego thing, it is a consistency thing. People go mad about getting
higher end grinders, machines, etc... because they are trying to control for
all possible variables. Espresso is incredibly finicky about those variables,
but you can control for them with the right equipment.

It is pretty easy to demonstrate that the higher end burr grinders have
greater adjustability and consistency than the lower end ones. It is also
totally obvious that they are needed on any higher end machine.

I used to think it was all bullshit too, then I got a Silvia, started with a
blade grinder, then a low end burr grinder, then a rocky before I could
finally get the grind both fine and consistent enough to pull a proper shot.

It isn't a subtle difference between a good shot or a bad one, anybody can
tell the difference.

~~~
Retric
EX: [http://www.drbunsen.org/coffee-
experiments/](http://www.drbunsen.org/coffee-experiments/) _Based on this
analysis, subjects did not show a statistically significant preference in
coffee brewed from a blade grinder or burr grinder._

First off only ~1/3 of coffee drinkers take it black which masks a lot of
taste variation.

Second, taste sensitivity varies widely.
[https://en.wikipedia.org/wiki/Supertaster](https://en.wikipedia.org/wiki/Supertaster)

Put together well under half of coffee drinkers notice subtle differences in
grinding methods. Assuming the devices are setup to similar grinding levels
and use similar source beans.

Note: You can find examples on both sides of this issue. But, the blind taste
tests that repeat over time fail to provide the expected consistency.

PS: There are a few people that both notice _and_ care about these issues, but
they really are the minority of coffee drinkers.

~~~
HeyLaughingBoy
I'm kinda with you on the ego thing, but I will claim that there is a
noticeable difference (in brewed coffee, I'm not an espresso fan) between
beans ground with a good burr grinder vs a blade grinder.

I couldn't match the quality of my local Dunn Bros coffeeshop until I started
asking them to grind my beans when I bought them. Switching from my cheap
blade grinder to their in-shop one made the largest difference in taste.

~~~
Retric
Your assuming it was using there grinder vs. there grinder _settings_ that was
important. In other words proper technique vs. proper device.

Also, time sitting around post grinding is a large factor.

~~~
HeyLaughingBoy
Well, considering that simply by virtue of being completely different types of
device, there's no way I could match their settings with my grinder.

Yes, time is a factor, but a week after the beans were ground in store, they
still tasted better than mine, so...

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petra
I'm curious: Since the problem was clear to anybody in the field - temperature
control, and there's a whole field dealing with control where PID is bread &
butter,so it's quite simple to ask for a solution , why did it take something
unique and tinkering to add PID to coffee machines ?

why didn't companies in the field just implement this as part of their product
development(maybe aiming for the higher end) ?

~~~
the-dude
I was told by a professional coffee technician manufacturers experimented with
electronic temp sensors 15-20 years ago but they were prone to failure. Field
service is expensive. This is for the professional machine ( 2 - 3 groups ).
They have always used pressostats which are very reliable but they wear due to
arcing.

For the home market, lots of machines are not heat-exchangers and therefore
need to run a lot cooler ( 100c instead of around 120c ). A pressostat does
not work well in this range and they just mount cheap thermostats.

~~~
abernson
This is more or less what I've heard. Early espresso machine tech was based
off mechanical relays, and they didn't play well with early electronic temp
sensors. Also, temperature stability was not really a thing anyone was talking
about to that degree, so it wasn't a priority for manufacturers until noise
was raised.

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the-dude
Well, I just have to shamefully plug the meCoffee PID (
[https://mecoffee.nl](https://mecoffee.nl) ). The product is just picking up a
bit of steam.

Disclosure: mine.

~~~
peapicker
Super cool! I'm tempted to up my Silvia's game (I've a v2 from ~2003), but the
lack of iOS app has me less likely to go there -- although I know you're just
getting off the ground and things take time. Nice work all around!

~~~
the-dude
You should definitely PID your machine, the increase in taste and consistency
is amazing.

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attaboyjon
Before we had reasonable espresso in Austin, I had my own PID'd Silvia. I had
had good coffee Vivace in Seattle and wanted to replicate it.

But boy was it a lot of work, your home-roasted beans have to be the right
freshness, the milk has to be super fresh and your tamping technique has to be
spot on.

Now that we have good coffee in Austin I cant see going back to doing it
myself.

~~~
adevine
Meh. I live in Austin, and I have yet to find a shop that makes espresso
drinks as well as I do (at least to my taste).

Don't get me wrong, Austin has some great shops. However, I feel like there
was such a strong move away from the "burnt Starbucks norm" that all of the
good shops feature _extremely_ light roasted coffee that, IMO, doesn't stand
up in milk drinks well and is usually way too acidic for me. If you know of a
place that serves a great medium-roasted, chocolatey/nutty cappuccino, would
like to find it!

~~~
jowiar
Much like there was a "hop escalation" in IPAs, there's definitely been a
"sour escalation" in coffee. It's fallen off a bit in recent years, but around
2012, it was bad (I'm looking at you, Intelligentsia!).

Roasters became accustomed to the sourness of the coffee, to make each new
coffee taste "right", they had to make it more, and more sour. For those of us
who didn't consume coffee in quite the volumes of the professionals, it didn't
go over well.

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polishninja
PID Controller, if you don't know what one is. (I didn't)
[https://en.wikipedia.org/wiki/PID_controller](https://en.wikipedia.org/wiki/PID_controller)

~~~
ashmud
If you've worked in industry and/or programming PLCs, you've probably come
across PID loops before.

Maybe not as accurate, but a simpler explanation: [http://plchowto.com/plc-
pid/](http://plchowto.com/plc-pid/)

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acveilleux
PIDs are great for espresso boilers where you want water around 202F (sea
level), so below boiling. My home machine with an 800ml brew boiler stays
within +/\- 2F all day with the PID. My previous machine without PID could
barely keep it in a +/\- 5F range.

For steam boilers, pressure stats are actually quite effective, especially as
they get larger.

~~~
adevine
Interestingly, I've read an article that explains why it's easy to make a
great cup of coffee in Denver. The boiling point of water in Denver is 202, so
you can add coffee to boiling water and it's right at the right temp
(something that would be a big no-no at sea level).

~~~
tzickles
link? would love to read!

~~~
jamessb
I don't know the article, but there are many sources for the individual
claims, e.g.:

* Denver is at 5,130–5,690 ft (1,564–1,731 m) [0]

* The boiling point of water at this altitude is between 201 and 203 °F; at sea level it is 212 °F [1]

* "Your brewer should maintain a water temperature between 195 to 205 degrees Fahrenheit for optimal extraction. Colder water will result in flat, under-extracted coffee, while water that is too hot will also cause a loss of quality in the taste of the coffee." [2]

[0]:
[https://en.wikipedia.org/wiki/Denver](https://en.wikipedia.org/wiki/Denver)

[1]: [https://en.wikipedia.org/wiki/High-
altitude_cooking#Boiling_...](https://en.wikipedia.org/wiki/High-
altitude_cooking#Boiling_point_of_pure_water_at_elevated_altitudes)

[2]: [http://www.ncausa.org/About-Coffee/How-to-Brew-
Coffee](http://www.ncausa.org/About-Coffee/How-to-Brew-Coffee)

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deutronium
PID temp controllers are also used a lot in homebrewing especially for
controlling mash temperature.

You can use the PID to maintain the temperature of the wort at ~65C by passing
the wort through a heating element and a temperature probe (this is called
Recirculating Infusion Mash System).

~~~
michael_h
I've found that the mashing temperature of the venerable 'huge cooler wrapped
in bath towels' is unbelievably stable.

~~~
deutronium
Yeah, that's true, although using RIMS/HERMS lets you performed stepped mashes
too and to some degree helps with clarity as the wort is constantly filtered
through the grain bed.

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caligastia
Anybody had espresso from a Mirage?

[http://www.keesvanderwesten.com/mirage-special-
features.html](http://www.keesvanderwesten.com/mirage-special-features.html)

Awesome use of a PID loop.

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thatcat
Does anyone know what the thermal stability system, which is more precise than
the PID on the graph represents?

~~~
abernson
Hi! Disclaimer, I wrote the piece for LM.

That's a graph from La Marzocco's internal documents and represents the total
heat stability architecture of their machines, including boiler and grouphead
design, preheating, tuned PIDs, etc.

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abernson
Hi everyone, I'm the post author. Feel free to ask me any questions and I'll
answer as best I can.

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lafar6502
is anybody buying $7K home coffee machine + only $500 for side panels and $200
for flexible steam pipe?

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brunoqc
Is there any proof that a PID is worth it?

