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.
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).
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]
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/)
I have a PID'd Silvia (https://www.seattlecoffeegear.com/pid-retrofit-kit-for-ranci...) 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.
I PIDed my Silvia as well. Seems to work well, though my heat exchange machine w/o a PID seemed to make better espresso (at several times the cost). These days my schedule has me leaving early so the machine is gathering dust in the garage.
When I was in Seattle this spring I made a tour of Vivace, Victrola, et al. Really fantastic stuff going on there. Here in the bay area everyone seems to like sour notes. I feel I beat out all the local shops with my home setup. Schomer definitely beats me out, though.
I've had cheap (~$100) burr grinders and still got too much dust in my ground for a proper-tasting espresso. Bought a Nuova Simonelli MCF (back when they were $350 instead of $600) and the commercial-level burrs and worm-gear infinite grind adjustment made my espresso incredibly better. Details on features of a grinder like this:
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.
EX: 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.
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.
Brewed coffee != espresso. I think that might be the essential piece you are missing. Espresso is brewed at very high pressures and as a result the grind size and consistency has a large impact on the resulting shot. The difference is not at all subtle and is quantified by the extraction time for each shot.
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.
As someone else noted, drip (brewed) coffee is a different beast than espresso. A blade grinder will probably do you just fine for that.
Espresso is brewed under pressure, if you don't have a consistently fine grind then the water will pass straight through without extracting any of the flavor. If your grind is too fine, then it will block the machine and you'll get a bitter extraction.
Again, this isn't a subtle thing. If you've had a real espresso machine (one that has a pump that applies the proper pressure) then it immediately becomes obvious that you need a consistent grind that you can adjust.
The variable you track is generally the length of the extraction, ie, how long it takes to get an ounce or an ounce and a half of espresso for a given amount of time. (aiming for 16-22 seconds or so) Too fine a grind and you'll block it up and you'll never get the oz, too coarse and it will all come out too quickly. You often need to adjust the grind minute amounts every day based on local temperature, humidity and the age of the beans.
This isn't audiophile stuff, it is obvious to anybody who makes espresso and actually wants it to taste good. (ie, isn't drowning it in milk, sugar and syrups)
While I understand where you're coming from on this with respect to high-end audio and other fields where eye-watering price tags are applied with poorly-defined reasons, this isn't the case here.
The espresso process is EXTREMELY finicky and highly sensitive to initial conditions. Recipes vary from bean to bean, machine to machine, and based on personal preference, but they all generally specify the same 3 things: the mass of coffee going in ("dose"), the mass of the resulting shot, and the time for the extraction to complete.
I typically am pulling shots with Madcap's Third Coast blend. In their shop they target an 18.5g dose yielding a 31g shot completed in 25 seconds (with no pre-infusion). The dependent variable here is the shot time. Anything +/- 4 or more seconds is dumped in the sink as completely undrinkable. The difference is not at all subtle - the shots are awful even to a novice palette.
The reason we have PIDs (and rotary pumps, heated group heads, calibrated tampers, doses measured to the 1/10th gram, etc) is to control every last variable that will impact this process. Every variable here can and will create wild swings in the resulting shot time, so we fix everything we can as accurately as we can to avoid dumping $1 worth of espresso down the drain. With everything else fixed, what we then control as the independent variable is the size of the grind.
This then is how espresso is tuned to land within the time given by your recipe. Grind finer (smaller particles), the process will take longer. Grind looser (larger particles), the process will run shorter. Anything more than 3 seconds one way or the other is another dollar bill down the drain. Very small changes in grind size can yield very large changes in the resulting extraction time. Every time you miss the mark, another dollar bill hits the sink.
As a result, grinder performance is probably the single most important piece of the espresso puzzle, and it's easy to quantify the difference.
Commercial coffee grinders are periodically calibrated to ensure they are providing the proper grind. When new both the $100 unit and $700 unit would likely provide similar results. Over time the commercial unit (built to handle higher volume) would remain in-spec without calibration for a consumer user whereas the grind of the $100 unit would likely degrade from wear.
What's an unforseen side-effect of so many people posting about their PIDed Silvias on the Internet that I noticed people who were hesitant to buy a Silvia because they thought too many people were manually correcting for a design flaw.
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).
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.
Agreed. Much as I love shiny kit, and RIMS/HERMS seems fun, I've never had my big cooler mash tun drop by even one degree C over 90 minutes, even without bath towels.
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.
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!
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.
Thanks. Yes it can, we already acquired a Classic and will produce a manual and video for it. But we can guide you through by email.
The meCoffee can be installed in practically every espresso machine which has no electronics of it's own. It is Faston(tm) connectors all the way down...
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!
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) ?
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.
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.
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.
45 comments
[ 2.8 ms ] story [ 105 ms ] threadFor steam boilers, pressure stats are actually quite effective, especially as they get larger.
* 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
[1]: https://en.wikipedia.org/wiki/High-altitude_cooking#Boiling_...
[2]: http://www.ncausa.org/About-Coffee/How-to-Brew-Coffee
http://www.freshcup.com/high-altitude-brewing/
http://sprudge.com/in-colorado-delicious-meticulously-brewed...
I have a PID'd Silvia (https://www.seattlecoffeegear.com/pid-retrofit-kit-for-ranci...) 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.
When I was in Seattle this spring I made a tour of Vivace, Victrola, et al. Really fantastic stuff going on there. Here in the bay area everyone seems to like sour notes. I feel I beat out all the local shops with my home setup. Schomer definitely beats me out, though.
https://www.seattlecoffeegear.com/nuova-simonelli-mcf
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.
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.
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
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.
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.
Also, time sitting around post grinding is a large factor.
Yes, time is a factor, but a week after the beans were ground in store, they still tasted better than mine, so...
Espresso is brewed under pressure, if you don't have a consistently fine grind then the water will pass straight through without extracting any of the flavor. If your grind is too fine, then it will block the machine and you'll get a bitter extraction.
Again, this isn't a subtle thing. If you've had a real espresso machine (one that has a pump that applies the proper pressure) then it immediately becomes obvious that you need a consistent grind that you can adjust.
The variable you track is generally the length of the extraction, ie, how long it takes to get an ounce or an ounce and a half of espresso for a given amount of time. (aiming for 16-22 seconds or so) Too fine a grind and you'll block it up and you'll never get the oz, too coarse and it will all come out too quickly. You often need to adjust the grind minute amounts every day based on local temperature, humidity and the age of the beans.
This isn't audiophile stuff, it is obvious to anybody who makes espresso and actually wants it to taste good. (ie, isn't drowning it in milk, sugar and syrups)
The espresso process is EXTREMELY finicky and highly sensitive to initial conditions. Recipes vary from bean to bean, machine to machine, and based on personal preference, but they all generally specify the same 3 things: the mass of coffee going in ("dose"), the mass of the resulting shot, and the time for the extraction to complete.
I typically am pulling shots with Madcap's Third Coast blend. In their shop they target an 18.5g dose yielding a 31g shot completed in 25 seconds (with no pre-infusion). The dependent variable here is the shot time. Anything +/- 4 or more seconds is dumped in the sink as completely undrinkable. The difference is not at all subtle - the shots are awful even to a novice palette.
The reason we have PIDs (and rotary pumps, heated group heads, calibrated tampers, doses measured to the 1/10th gram, etc) is to control every last variable that will impact this process. Every variable here can and will create wild swings in the resulting shot time, so we fix everything we can as accurately as we can to avoid dumping $1 worth of espresso down the drain. With everything else fixed, what we then control as the independent variable is the size of the grind.
This then is how espresso is tuned to land within the time given by your recipe. Grind finer (smaller particles), the process will take longer. Grind looser (larger particles), the process will run shorter. Anything more than 3 seconds one way or the other is another dollar bill down the drain. Very small changes in grind size can yield very large changes in the resulting extraction time. Every time you miss the mark, another dollar bill hits the sink.
As a result, grinder performance is probably the single most important piece of the espresso puzzle, and it's easy to quantify the difference.
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).
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.
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!
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.
Disclosure: mine.
The meCoffee can be installed in practically every espresso machine which has no electronics of it's own. It is Faston(tm) connectors all the way down...
Maybe not as accurate, but a simpler explanation: http://plchowto.com/plc-pid/
why didn't companies in the field just implement this as part of their product development(maybe aiming for the higher end) ?
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.
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.
http://www.keesvanderwesten.com/mirage-special-features.html
Awesome use of a PID loop.