Change one variable at a time - good advice?

Beginner and pro baristas share tips and tricks for making espresso.
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#1: Post by Psyd »

another_jim wrote:This is why I call "one variable at a time" the moron mantra. The variables are not independent, and by changing one at a time, you are just accommodating the current choice to the bad choices you made earlier
It may be true that the variables are interdependent, but there are a slew of them. Changing one at a time gives you and idea, to a certain degree, of what that particular variable does. Imagine you inherited a stereo that was very complicated high-end schmata. Except, all of the screen printing had washed off the face, so all of the knobs weren't labeled. I'd start out by setting them all in the middle, (think of this as the 'golden rules' of 14g, thirty seconds, thirty pounds, 60 ml) and then start moving one knob at a time to see what it did to the sound. Yeah, I'm not ringing in my system moving one knob at a time, but I'm figuring what effect each has. Eventually, I'll tweak each into where I want it for a particular record or disc, or whatever, but moving them all a bit each way and seeing what I like is going to take a LO-O-OT longer, and I'm not going to be sure how I ended up there, and as soon as I change discs, I will probably just end up trying a bunch of knob turns until I'm happy, or tired. Knowing what knobs do what is a far handier tool to have in your tool box, and eventually you start to feel how they are inter-related. Eventually. If you stick with it and have an experimental nature.
I am a professional sound engineer. I have racks and stacks of kit with knobs on it. Heck, the smallest console I have has more'n a hundred knobs in it alone! While setting up a band, from Classical to thrash-metal, I find that I'm rarely turning more'n one knob at a time. And they are VERY inter-dependent. I do turn one and see that what I've done is what I wanted, and in the right amount, before I go to the next. Sometime I do have to come back and add a bit or subtract a bit of the previous change that I made, but I have to wait to see how the succeeding change effected the following one.
You can graduate to changing a buncha variables at once, but I'd suggest that you wait until you learn what each knobs do before you go messing about.

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#2: Post by zin1953 »

Psyd wrote:You can graduate to changing a buncha variables at once, but I'd suggest that you wait until you learn what each knobs do before you go messing about.
Exactly! There is a huge difference between an expert and a novice. It's much easier for an expert to know x, y, and z are all off. The novice would be best served by tackling one variable at a time, but in no way does that translate to sticking to "one at a time" for the rest of one's life.

By taking it one step at a time, it is easy/easier to see, taste, and understand what happens with this is changed, or when that is changed. Keep the temperature the same but alter the dose . . . keep the dose the same but alter the temperature . . . adjust the grind, and repeat -- it really helps you understand the part that each variable plays, AND how they "inter-play" in the overall scheme of things.

Just my 2¢. YMMV.

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#3: Post by RegulatorJohnson »

why dont you just put them all on 11?
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#4: Post by Psyd (original poster) replying to RegulatorJohnson »

"Exactly. What we do is, if we need that extra push over the cliff, you know what we do?"
"Put it up to eleven?"
Eleven. Exactly. One louder.
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#5: Post by another_jim »

Psyd wrote:It may be true that the variables are interdependent, but there are a slew of them. Changing one at a time gives you and idea, to a certain degree, of what that particular variable does.
I'm sorry to pick out just one poster, since all of you keep falling hook, line, and sinker for this patent nonsense. Try, for a bracing change of pace, thinking in terms of real things instead of either in fancy sounding words or in symbol manipulating objects like control panels. After all, it's an espresso, not a Turing, machine.

If someone tries a suit that's three sizes too small, telling them to buy the suit, then go to a tailor and change just one thing at a time, the right sleeve, the left cuff, etc etc, is really, really bad advice. Newbies are prone to do everything wrong on their espresso machine, so telling them to change just one thing at a time is also very bad advice.

It's best to start out by specifying a complete set of all the variables that are known to work. My suggested candidate for the best overall set of variables for a newbie to pick at the outset are the ones the machine and grinder were designed to do: 14 gram doubles, 25 second, 50 mL shots, 11 bar blind pressure (it's a vibe pump), 85C to 90C at the bottom of the puck at the end of the shot, or 90 to 95C at the top of the puck throughout the shot. It is my opinion, based both on my experience and on common sense, that it is easier to make technically good shots using this set than using any other.
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#6: Post by CRCasey »

Of those five good ideal starting points most people new to espresso will have measurements for what maybe three, but more likely two of them. Let's assume they can do time and volume of fluid.

So to get a handle on things you should at least have the additional equipment that follows:

A Scale, .1 gram is nice. If you want .01 gram scales are good. One of each would be peach.

Build a pressure gauge that will fit onto your PF. If you have a couple of bucks extra add a needle valve to simulate the flow suggested above, dial the machine to 9 Bar with it.

Finally add a Styrofoam cup and a cheap digital thermometer. See if you are getting the range of temps out of the PF you expect (as above).

There are expensive ways to read these numbers and there are cheap ways.

Either way those numbers can not transfer from one person to the next, and are only good for your own reference. So keep a book of what you like and what you don't like, and have some numbers so you can go back to what you like more easily.

If you can reproduce what you like with your numbers who cares what the readings are. As long as they are good for you.

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#7: Post by HB »

CRCasey wrote:If you want .01 gram scales are good.
Is this a typo? One-tenth of a gram accuracy comes out to around half a coffee bean, which I hope we all can agree falls well within "close enough" to be considered consistent dosing.
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#8: Post by CRCasey »

Sorry, I had one sitting there. Is it good for making a taste judgment, not so much.
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#9: Post by GC7 »

If you have a suit that is three sizes too small there are quantitative measurements that can be made to determine all the variables that need to be altered. There is therefore no need to alter one sleeve at a time. That is a silly and worthless analogy if a new home espresso enthusiast can't make a similar quantitative evaluation of what to change to get a better drink.

Any scientist or anyone trained in scientific method will tell you to alter one variable at a time if the goal of the experiment is to actually understand the process. If you want to play the lottery then change every parameter at once and hope for a good result.

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#10: Post by Peppersass »

First, I'd like to thank Jim for his useful and informative reply to my post under the Basket Overdosing thread, and his positive and encouraging tone. He's the only one who actually tried to answer the questions I asked instead of warning me that Silvia will doom me to failure, suggesting I'm a half-assed newbie who won't get consistent drinkable shots for months, or holding forth on the best way to approach complex systems with interdependent variables. Jim gave me sound recommendations on buying a bottomless PF, 1/10 gram scale and a different basket (all of which I'd already done) and gave me a great suggestion for where I might get good SO coffee suitable for 14g shots. The only remaining question that still hasn't been answered is whether anyone has successfully pulled 14g shots on a Silvia. It might save me some time to know that.

Most of the other replies contain a lot of chest pounding and irrelevant theorizing. In the course of arguing with each other, I think some of you are missing the point.

The Golden Rule says (approximately) 14g, 60ml, 25-30 sec. Strong arguments have been advanced that Italian espresso machines are designed for 14g doses. That's what they use in Italy, without all the fancy dancing and tamping done here in the U.S. to get an updose to pour correctly. If this was all I knew, then I would undoubtedly begin by setting one of the variables, the dose, to 14g.

But I've learned that popular espresso blends are designed for updosing, and there are posts claiming Silvia does better at higher doses (perhaps this is due to the factory brew pressure setting being too high?) Further, of the dozens of Silvia shot videos I've watched, I'd be willing to bet not a single one used a 14g dose. The typical technique is to overfill the basket, tap, fill again, level with a personal favorite method, tamp, tap the side (maybe), tamp with anywhere from light to heavy pressure, polish, shake out loose grinds (maybe), do a little dance, bend over, kiss one's ass, pray for a god shot, etc. I have no doubt not a one of those baskets contained less than 16g of coffee, and most of them were probably in the 18g-21g range.

So what's a newbie to do?

Well, I thought I'd try it both ways. My plan was similar to what Jim suggested with his five key variables. Having not yet identified a coffee suitable for 14g doses, and because of the possibility that Silvia's factory pressure setting may be somewhat high for that dose, I thought it would be best to start with an updosing technique like what I saw in the vids, try to dial in the grind for volume and time, and work on the distribution to get a decent pour -- all the time tasting to judge the effects of each change. It shouldn't be too hard to rig a thermocouple (which I have) to check the temp at the bottom of the puck and adjust the PID accordingly (and I may need to experiment with flushing the group just before a shot to heat it up if the machine's been idle.)

Yeah, I realize only one thing should be changed at a time (where possible), and also realize it will probably take a lot of time and many sink shots to get anywhere close to an acceptable result. I also realize I might get sprayed with coffee, might get frustrated, and might have some very disappointing sessions. I'm prepared for all that.

Ideally, I would move to the 14g dose after getting a decent and consistent updosed shot and identifying the right coffee for 14g. I hope it happens that way, but I understand that Silvia's idiosyncrasies may complicate the effort. I may not be able to get a consistent or even decent updosed shot if Silvia's brew pressure isn't right. I might have to adjust the OPV for less pressure. I don't know yet. Yes, I was expecting I might need a pressure gauge at some point, but there are some accuracy questions associated with using one and I'm not ready to delve into them yet.

It seems to me that it's just as valid to try a 14g dose *before* trying more involved operations like measuring/adjusting pressure. What if my 14g doses taste better than 18g doses without making any machine measurements or adjustments at all? I'm not saying it's likely, but it's certainly easier to try than fooling with the pressure, especially if I'm not sure about the accuracy of the gauge. Having learned that the popular blends aren't suitable for the 14g experiment, my main concern was getting the right coffee. That's why I asked about it.

My point is that dose is one of the variables I can try to change on the road to producing consistent good shots. I don't see why I necessarily have to make the machine produce a consistently good updosed shot before I try that, especially if it proves difficult to do so. The worst that can happen is that it won't work, and I'll have to turn my attention to other variables.

Heck, once I find the right coffee, there's no reason why I can't start with 14g doses, dial them in as best I can, and compare with updosing one of the popular blends.

I appreciate the advice on changing one variable at a time, but it sort of put me off.

By way of introduction: Although I'm new to espresso, this is not my first rodeo. I have a fair amount of experience with systems that have interdependent variables. I'm also a veteran of some expensive and complex hobbies like high-end audio, wine, and amateur radio, all of which take a lot of patience to learn, feature many interdependent variables and have results that can be evaluated via scientific measurements or subjective sensory judgment. I'm highly technical and enjoy solving difficult problems. I'm also off-the-charts intuitive (for Myers-Briggs fans), which hopefully adds some art and creativity to my endeavors.

These are some of the reasons I selected Silvia. I'm intrigued by the challenge and the learning experience. I like working with test equipment and there's a decent chance I'll make further mods to my Silvia (I'm the sort who doesn't hesitate to open a multi-thousand dollar piece of gear, even while still under warranty, to fix it or make it better.) I read in one of the "dump on Silvia" threads that what is learned by trying to make Silvia produce good shots is useless information that can't be transferred to other, more forgiving equipment. Perhaps, but I suspect that's not entirely true. I think I'll learn a few things and have a lot of fun. Heck, if I get too frustrated I'll just sell the thing and buy a machine with an E61 group head! No big deal.

Why not do that now instead of buying Silvia? Can I afford a better machine? Yes. Can I afford to skip all the rigmarole and go straight to a multi-thousand-dollar, top-of-the-line machine that will pull great shots with little effort on my part? Perhaps. I might end up doing that. Do I want to start that way? No. There's a difference between being able to afford and being ready to make a major commitment.

First, I want to thoroughly understand the interplay of all the many variables that go into producing a good shot. I want to learn how to make a good shot without the help of an E61 group head. I want to thoroughly understand how Silvia works. I want to figure out if it's worth investing in simultaneous frothing capability to make milk drinks for my wife, my daughter or company (right now, I don't even know if they'll want them.) I want to gauge just how much my palate can detect. I want to determine how important it is to me to squeeze every flavor note out of the coffee versus just getting a decent beverage in the morning (I've been drinking tea for the past five years, folks.) And yeah, I know Silvia muddies the shot, but I also know it can produce a tasty shot nonetheless. I want to know if espresso is critically important to me, or just a passing fancy (if the former, then I'm likely to skip the intermediate machines and go for the best.) Silvia seemed like the minimum and perfect entry level machine to determine these things and learn about making espresso, plus she has excellent resale value if I decide to upgrade. There is a vast body of work on tweaking and modifying the machine. You may not think the aggravation is worth it, but you are not me.

I guess this means it's not 100% about drinking a great cup of espresso whenever I want. Yes, that's a huge part of it. But for me, it's also very much about the process of getting there.

Sorry for the semi-rant. I have nothing better to do while I wait for Silvia... (Every time I hear that name I can't help but think of Albee's "The Goat, or Who is Silvia?", in which the hero falls in love with a goat named Silvia. It's quite shocking news to his wife.)