Posted Sun Aug 24, 2003, 5:02pm Subject: Some extraordinary results by reverse temperature surfing
My coffee buddy, Richard, bought my Silvia/Rocky setup. For the last few weeks he's been complaining about sub-standard shots, describing them as bitter / harsh. My answer was always the same: "Your temperature is off." He tried temperature surfing but still complained of good shots one day, terrible the next, and no great shots at all. Yesterday we got together for the Rocky/Mazzer shootout rematch (click here for the first match results by CraigA). Afterward, we turned to diagnosing Silvia. Another CoffeeGeek, David Morris, mentioned the idea of temperature surfing after reaching max temperature. I wanted to investigate this idea of "reverse temperature surfing."
We did a lot of temperature trials to reverse temperature surf Silvia accurately. Normally when you temperature surf, you introduce water into the boiler, wait for the heating element to come on, then wait n seconds for the water to heat up to your target temperature. Problem is, my measurements showed variance, probably because split-second response can make a big difference (e.g., two seconds too much water and you're off by several degrees), not to mention "warm versus very hot" Silvia variations. I also noted that his machine put out a lot of water, almost 10oz in 30 seconds. Again, that makes it hard to temperature surf accurately by introducing water.
So instead, we tried the other direction, hence why we call it "reverse temperature surfing." We introduced water until the boiler came on. Then we waited for the heating element to turn off. Then we plotted the drop off in temperature (1 minute, 2 minutes, 3 minutes, 4 minutes, 5 minutes... really boring stuff). By trial and error, we found that 2 minutes after the boiler clicks off with a well heated Silvia, the temperature reached 201F. At first we would get variances of 196, 197, 199, 199... and then 201, 201, ..., 201. It was that dead-on, time after time after time. His wife is a statistician and says we'd have to take at least 25 measurements to have any true statistical certainty; we stopped after six consecutive results of 201F. Obviously this type of temperature surfing requires lots of patience, since you're waiting about three minutes to get to the right temperature by the time it heats up to boiler shutoff and cools down to your target temperature.
To make an already long story short(er), this technique seemed to produce pinpoint accurate temperatures. Since the boiler is cooling (not heating as would be the case in 'normal' temperature surfing), we suspect the temperature stability during the shot is enhanced. The Intelligentsia Black Cat shots we pulled yesterday afternoon using this technique were some of the best Silvia has ever produced. Two shots from the Silvia/Mazzer Mini trial were "rock your world" calibre and we rated the third "very good to excellent". I barely escaped from his kitchen with my grinder. :-o
I've always been a little skeptical of all this fussing about temperature accuracy, PIDing, and so forth. I'm now convinced it is one of the most important elements to superior espresso results. Any patient Silvia owners care to validate these results? We used the styrofoam cup measuring technique described in My Espresso is Cold!
Ah, I forgot to mention that we had also pressure modified his machine a couple of weeks ago down to 9 bar (it was 11 bar). He reported that the results were unchanged -- until this weekend. Three great shots do not prove a theory but sure got us thinking. We plan yet another matchup in a few weeks, the Silvia/Rocky/Mazzer versus Valentina/Rocky/Mazzer Slugfest II. Stay tuned.
bellis Senior Member Joined: 20 Nov 2002 Posts: 94 Location: Tulsa Expertise: I live coffee
Espresso: Andreja Premium Grinder: Mini Mazzer Vac Pot: Not Yet Drip: French Press/Modded Clarity Roaster: 5kilo Roaster
Posted Sun Aug 24, 2003, 10:15pm Subject: Re: Some extraordinary results by reverse temperature surfing
I had read many threads and/or posts about temp surfing the silvia before getting my very own machine. When I got my silvia i realized i would need to do some temp surf experimentation to find my sweet spot. Since my silvia was a newer model with the 100c temp stat instead of the 110c that older models had; I had to adjust my temp surfing times a little differently.
I first started out with hitting the brew switch and running water thru the empty portafilter until the heating light came on. I would stop the water, fill the portafilter with coffee, tamp etc. and run the shot at the 1min point, and then i slowly worked my way up to 2mins. I did that for a while and then started waiting a little longer and finally found consistency at 3mins from the time the heat light comes on. I have been doing this with consistent sweet spot results.
Therefore, i'm basically doing the same thing as your reverse temp surf since the heat light usually turns off just before a minute and 2 mins later is 3mins. Glad to see others have found this method to be winner.
espressoDOM Senior Member Joined: 1 May 2003 Posts: 2,188 Location: Bay Area Expertise: I love coffee
Espresso: WEGA Lyra (vibe) Grinder: Mazzer Mini Vac Pot: (no more coffee equipment) Drip: French Press Roaster: Hot Top Roaster; Fresh Roast...
Posted Mon Aug 25, 2003, 10:33am Subject: Re: Some extraordinary results by reverse temperature surfing
Good details... Dan... In all the chaos of trying to get a good shot out of Silvia I forgot completely about the surfing aspects of Silvia... I have just left her on for long periods before making espresso....
I am going to have to play with temp surfing in an attempt to make a better espresso....
ps I am trying Allegro beans this week... Black Cat next month
DOM...evil genius ...Up to no good in espresso at all times... VIVA la parts de Espresso
gscace Senior Member Joined: 19 Dec 2001 Posts: 237 Location: Laytonsville, MD USA Expertise: I live coffee
Espresso: La Marzocco Linea 2AV, Astra... Grinder: 3 Mazzers Robur, Kony,... Vac Pot: Cona D, Hario Nouveau Drip: Technivorm Roaster: Has Garanti 1kg. electric
Posted Mon Aug 25, 2003, 11:38am Subject: Re: Some extraordinary results by reverse temperature surfing
Nice report and absolutely on the money. Actually, the reverse temperature surfing scheme should be way better than the normal method. The problem with the reverse method is that the method is quite time consuming if you are doing multiple shots for several people. But it should be quite repeatable. I'm glad to see that you have become a convert to the idea that temp reproduceibility is key. Next step is PID.
I believe that the PID / pressure controlled Silvia / Mazzer mini can go toe to toe with nearly any machine /grinder combo on the market. I think that you'll find that out when you do the La Valentina Mazzer Rocky Mazzer slugfest, particularly if the Silvia uses the LM basket or the LM knockoff pf and Swift triple basket.
See Alan Frew's article on home machine comparisons as well. It's on this site under articles, I think.
I agree! Of the nearly dozen shots we pulled, two of the best three were Silvia/Mazzer. Much of the HX/E61 benefit is convenience and consistency. I'll even quote myself:
The real question: Is there a reason not to buy an HX machine? With the modifications you've made to Silvia, your straight shots are hard to beat. I never PID'd Silvia before upgrading, but Mike Walsh (CupaJoeKid) pulled some shots from his and they were excellent. I have a new appreciation for temperature control.
OTOH, having recently gotten an HX machine, I agree that steam on demand is a big bonus. I'm perhaps not a good person to ask. I upgraded, inline plumbed, and put in a drain. No refilling, no emptying driptrays, just pull and steam. Funny thing is, adding the drainline was probably the biggest "bang for the buck" in terms of improving my enjoyment of preparing my daily espresso / latte. It cost only about $20 in plumbing and a short half day's work. Go figure.
When it comes to milk-based drinks, Silvia already steams a very good microfoam. La Valentina is definitely better in terms of consistency and the steam is a lot drier (no sputter, no huge "hills and valleys" of steaming strength, and no waiting). Nonetheless, I believe it is more about convenience than side-by-side superiority of one result over another. The bottom line: How much are you willing to pay for convenience?
As an aside, just for giggles I took the same measurements on La Valentina; after the group flush, it seems to have about a 2-3 degree swing between 198-201F. I also noted that inlet temperature does matter for an HX machine. I have a filter system from Chris' Coffee that is also hooked up to the ice maker and a small faucet. My wife was preparing for a party and drained off a couple gallons from the faucet, flushing the system with fresh cool water. It took me a few minutes to figure out why La Valentina's temperature was suddenly cooler.
I don't know if one-degree consistency adds up to anything detectable by mere mortals.
Posted Wed Dec 8, 2004, 9:16pm Subject: Re: Some extraordinary results by reverse temperature surfing
Interesting....Now, first let me tell you that I am a newby and new owner of a Silvia/Rocky and I am trying to apply and gather as much info as possible from you guys here at CoffeeGeek but at this point there may be a slight difference with my Silvia and that is that since I am in Lima, Peru we have 220volts and my Silvia is a 220-230 unit and I have read somewhere that my Silvia would heat up faster than a 110 volt (US version) one?. I found out that after the brew light comes on it takes between 49 to 51 seconds to when the light turns off. Therefore maybe I would need to adjust and find my particular "sweet spot" temperature point for brewing?
My guess is that I should probably use a faster time when "temp surfing" (20 seconds). If I am doing "reverse surfing" the 2 minutes waiting time should be the same since cooling is not affected by different voltage. Am I right?
Posted Wed Dec 8, 2004, 9:33pm Subject: Re: Some extraordinary results by reverse temperature surfing
Hmmm. It seems I've always been reverse surfing with my Gaggias and assuming this was normal temp surfing. Then again, the small boiler and high heating capacity of the Gaggias make them pretty much impossible to do a 'heat on' surf since the element is on for such a short period.
As for the different voltage thing, I think the 220-230V Sylvias have a more powerful heating element than the 110V ones so there could be more overshoot - this would then change the reverse surf period.
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