Effects of high humidity on lever machine's extraction

[HB]

We're vacationing at the beach this week and the weather has been variable: Thunderstorms in the morning, clearing around noon, scattered showers. Current conditions are:

Wind: From SW at 5 mph
Humidity: 73%
Pressure: 30.07 in.
Dew Point: 77°F

Below is the espresso from the first day:


Nice coloring, good flavor, rich persistent crema

Far from the best I've had from the Microcasa, but pretty good. Since the first day my shots have been iffy at best. I'm alternating between very slow flows with little crema and dark coloring (borderline overextraction) and too fast with weak flavor, non-persistence crema, and carmel coloring (underextraction). The change in grind setting between these two extremes isn't much -- less than one notch on the Mazzer. This is a much more dramatic effect than I would expect inland.

The house has air conditioning which should theoretically keep the humidity fairly constant, but I'm wondering: How much effect does humidity have on the grind setting in a climate-controlled environment?

Or am I looking at the wrong cause?

[malachi]

I doubt it is a single cause.
That being said, environmental factors have a huge impact on extraction. I can give you a ton of examples, but probably the best (and most simple) one is from a coffee bar that was in a large, industrial space. They had a massive HVAC system installed. The system was powerful enough and the space well insulated enough that, when hot, the AC only came on periodically and for a short time. The thermostat for the system, unfortunately, was located at the end of the space furthest from the doors (and far away from the espresso machine). In addition, the duct vents for the system were angled in a manner that blew directly onto the grinders. As a result, when it got busy and the doors would be opening and closing a lot, you would get this "ramp wave" sort of thing where temp and humidity would rise steadily (requiring steady adjustment of the grind) and then suddenly the AC would go on and it would become dramatically cooler and drier very quickly (requiring a drastic re-adjustment of the grind).
I've also worked in small spaces where the number of customers in the coffee bar changes the grind.

[HB]

I doubt it is a single cause.

Yes, I bet operator error is coming into play. Although I'm on vacation, Steve is at work, so I decided to ping him. Here's how our chat started:

Me: Hey Steve, it's great weather at the beach. How's the office?
Steve: Bite me.

I tossed out my theory about humidity but he wasn't buying. Here's some of his suggestions:

1. Begin by kneeling on the porch facing Seattle and saying a short prayer to the espresso gods.
2. Adjust the grind until you are almost choking it.
3. Pay extra careful attention to the distribution in the basket. His Rocky tends to clump, so he first grinds into a cup, then transfers. After which he does the "Chicago Chop" over the basket filled to heaping (this approach to distribution is popular at Intelligentsia). A clean swipe across... no downward pressure at all... none.
4. Follow with a good 35-40 lb tamp; really clean up your edges and let her rip.

For good measure, this morning I also did the "fast thwack" dosing, hoping that would improve the distribution. And indeed the mottling was much improved, despite the relatively low crema. Looking at the result for the initial moments, I thought it would be a real winner. Then in a matter of 20-30 seconds, the crema faded revealing the dark liquid below. It tasted overextracted too.

I've seen this "effervescence effect" with super-fresh beans. I'm using Black Cat roasted August 3rd, which is outside of its prime window. Is the source of my woes simply dud beans? (OK, I'm spoiled... my stock is older because I didn't arrange for a delivery at the beach. Next year I'll plan ahead).

[HB]

In addition to Steve's earlier advice, he offered a possible explanation for lackluster lever shots that I've never heard before: Suction. Before getting into that, let's take a peek at this morning's espresso. Note I pulled a new bag out of the freezer and adjusted the grinder 1/2 notch coarser, as it often necessary when switching to fresher beans:


Very slow ristretto, thin crema, lacks sweetness. Verdict = overextracted

Dialing in a lever machine is a royal pain when the grind setting is everywhere on the map. You only have two or three shots before the grouphead no longer functions as a decent heatsink; the fourth shot is invariably no better than "cappuccino worthy." Usually I can predict the grind setting day-to-day based on post-roast date. That hasn't proven at all true at the beach where interior humidity raises 15-20% by opening the door. Or at least that's my excuse...

Back to Steve's suggestion. He warns that new lever machines have very tight seals and cocking the lever can break the puck-to-basket seal. That is, if the piston withdraws quickly, air can be pulled up through the portafilter and dislodge the puck's seal, especially if the puck is thin for a single espresso. It's not an issue with older machines whose gaskets are no longer airtight.

The workaround is pretty simple: First of all, don't cock the lever too fast (guilty as charged). While there's a good risk of burning yourself, for singles he'll keep the portafilter just shy of tight as he initially pulls the lever, then snug it and continue. This avoids the piston "sucking" the puck from the basket, which can occur if the seals are airtight, the puck is solid, and there's some headspace.

Were it not for the grind being off, I expect this would have been a very good espresso. As it turned out, it was reasonably smooth and flavorful, tons of cocoa, but lacking sweetness and a rounded finish.

What's a barista to do when the grind is off and the machine's overtemp in 15 minutes? I was tempted to pull shots anyway knowing they'd be hot sink feeders only to get the grind setting closer, let it cool, then start again...

Note to self: Re-read Putting it all together.

[HB]

I thought that I knew what a godshot was. But this morning was an other-worldly experience as I witnessed the creation of a truly magical elixir. I tremble when recalling the moment... At first the earth shook. Then the sky split open as a choir of cherubs descended on golden beams leading to the Microcasa's portafilter. Fortunately I immediately slipped on a dark pair of sunglasses at arm's reach, otherwise my sight would likely have been lost.


All attempts to photograph the godshot failed

Words cannot describe the joy. Tears burned my reddened cheeks as I raised the cup to my lips. The photograph above was taken soon afterward; inexplicably all traces of the divine nectar are absent. Even the dark brown exterior of the cup has been transformed to pure white.


























(The above is an idealized fictional account borne of the author's failed attempts to pull a genuinely masterful shot from the Microcasa before vacation ends... three days and counting)

[IronBarista]

I figure it must've been great. You licked it clean.

[Walter]

I figure it must've been great. You licked it clean.

The cup??? Outside???? Wow!!!!


What kind of color do they use? I hope it ain't anything toxic....

You know, Dan, this thread has pretty much spoiled my - probably all too romantic - idea of taking a Micro Casa with me on vacation, just to get some very good espresso...

[HB]

If you can Walter, take a lever machine along on vacation. Although I've lamented about the espresso from the Microcasa this week, in truth the shots haven't been that bad. The "problem" is that my standards have moved up. To put it in perspective, almost half of the shots this week are on par with what I sampled from the better cafes in Seattle. None have been sink shots.
I'm reminded of the standards defined for judging (0 = unacceptable, 1 = acceptable, 2 = average, 3 = good, etc.). Since last year's workshop, I have the mental habit of scoring my own espresso as if it were served in competition. It's a humbling experience to approach one's work with such a critical eye. First of all, there is no shame in scoring an espresso "2". Average means well prepared by good cafe standards, not typical for the majority of the world's cafes, which we all know are sadly lacking. At last year's competition, I don't recall scoring anything higher than 4.0. My typical shots would score in the 2.5 to 3.5 range; my best would merit 4.5.

It's true that Elektra and I have't been reveling in fantastic espresso lately. The best so far this week are 3.5s and that's being kind. The worse flirted with a score less than 1 (!?!). But Monday is still days away.

[Walter]

Thanks for clarifying that, Dan....

I don't want to hijack your thread, but since you've addressed the issue I'd like to throw in another point: For me judging an espresso is quite a subjective task. Since I'm lacking any comparison with real good espressos I can only judge relative to my own progress over the months and occasionally it occurs that I consider a cup as almost "sinkworthy" whereas my wife and son still say it's quite good. So - is there a way to judge without comparison? I doubt it.

Regarding the Micro Casa: The original plan was to get the machine now, practice some with it and then - in almost 4 weeks - take it with me on vacation. But Elektra like most Italian firms are on holiday now and won't begin shipping until early in September. So I switched to Plan B and decided to get the machine at the beginning of my vacation either directly from Elektra or a vendor nearby (since that is less than an hours drive from where I will be) and become familiar with it during my vacation. But now it looks like I'm in for an unpleasant surprise: that this experiment might result in frustration.

But on the other hand I doubt I'll be able to leave it untouched in the box for more than a week. We'll see...

Someone knows an outstanding Cafe in the Udine region?

[Bob Barraza]

Dan, I just picked up on this thread, but I have a few comments.

First, I think that ambient humidity plays a huge role. Think of it as the first step in 'pre-infusion'. As beans absorb moisture they will expand.

Regarding the photo of your God Shot... exactly how much time are you spending in the sun?

Lastly, you are having much better results with your Microcasa than I with the 1983 model I am trying to restore. I have now installed a new gasket set, but still nothing but sink shots with a strong metallic taste. I am descaling the boiler at this moment to see if that helps.

I was planning on bringing it with me to the meeting tomorrow at CCC to see if you could give me some guidance, but it sounds like you will still be enjoying the coast. Next week.

Cheers

Bob

[HB]

So I switched to Plan B and decided to get the machine at the beginning of my vacation either directly from Elektra or a vendor nearby (since that is less than an hours drive from where I will be) and become familiar with it during my vacation. But now it looks like I'm in for an unpleasant surprise: that this experiment might result in frustration.

Mark's operation hints for the Microcasa will save you a lot of guesswork. To that I'll add some suggestions:

• Pick a forgiving blend temperature-wise
• Use a timer and scale to rachet up your consistency
• Dial in the grind with another machine you know well that doesn't overheat. The Microcasa runs about 3/4 notch coarser than my everyday machine; I can use this approximation to reach decent shot quality more quickly.

And of course the most important suggestion: You're on vacation, and as I understand it, you're in Italy. If it doesn't work out, share your woes with a sympathetic barista at a local cafe over some great espressos.

[HB]

While my shot pulling mojo is still lacking, today's espresso wasn't bad:


Nice taste balance, but weak crema mars an otherwise good espresso

I thank Steve for this helpful suggestions -- the last few days have been closer to how the espresso was flowing on day one of my vacation. For those shots that fell short of expectations, well, I will continue to blame humidity.

As a mental exercise, I decided to formally rate this espresso using the SCAA sensory score sheet:

Color of crema (hazelnut, dark brown, reddish reflection): 2.25
Consistency and persistence of crema: 0.75
Taste balance (harmonious balance of sweet/acidic/bitter): 2.5
Tactile balance (full bodied, round, smooth): 1.75
Overall: 1.5

The lack of crema and its iffy persistence really marred the shot; it wouldn't be overly harsh to mark it as a 0.5. On the plus side, the espresso was balanced, smooth, and had lots of chocolate sweetness. High-body shots elude me on the Microcasa and this one was no exception; otherwise the tactile score would have moved up appreciably.

For the technical judges: Dried basket thoroughly, wasted a few grams of coffee in spillage, good distribution and tamping, no scale used (volume measure), medium speed thwack, two taps at just past 3/4 full, overfilled and leveled with Chicago Chop, no downward pressure; 12 minute preheat, half-shot blank to warm portafilter, ten seconds preinfusion, two pulls, approximately 30 second extraction.

[barry]

no 1/4 scores, please.

[HB]

You're joking, I know, but it's a question I need to keep in mind...

I remember that 1/2 points were common at last year's SERBC. I'll ask at the judging workshop if anything less is too hairsplitting. It was John Sanders who said there would never be a 0.0 or 6.0, and one would hope there are very few scores below 2.0. So if you went by halves, that leaves only 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, and 5.5. It's not unlikely that the majority will score below 4.0, so only 2.0, 2.5, 3.0, and 3.5 remain. Only four numbers? Do 1/2 points still seem too coarse?

FWIW, the head judges were more concerned about consistency in scoring than anything. Last year was my first judging event, so the head judge shadowed all my scores. He "recalibrated" one of my espresso scores, which I still disagree with today. But that's a discussion for another day and another thread.

[barry]

i'm poking a bit of fun at your personal scoring, that's all.

but no 1/4 points is serious in the USBC. danny o'neill would do it just to hack off sanders, but he's about the only one who could get away with it.