Whatever happened to low brew temperatures?

[another_jim]

The "official" range of espresso brew temperatures is 90C to 95C, or 194F to 203F. The conventional wisdom is that darker roasts get lower temperatures, lighter roasts get higher temperatures.

I am rarely going much beyond the first pops of the second crack in my blends; so I'm no expert at lower brew temps in my own shot pulling. At Charlotte, we sampled several dark roasted blends; and they frequently tasted ashy to me and to others. When I trotted out the conventional wisdom suggestion of dropping brew temps down to the 194F to 198F range, people looked at me like I was nuts. And in this case, they were right; since even the dark roasts tended to go lemon-peel nasty below about 199F.

Is the conventional wisdom wrong? Have blends changed dramatically? I'd be curious to hear what people think has happened to the lower end of the conventional espresso brewing range.

[Matthew Brinski]

Jim, I'm glad you brought this up. This is a very interesting topic to me. It's interesting not only because of brewing and taste implications in general, but also because my home espresso is brewed at just under an altitude of 8,500 feet. The boiling point at this elevation, depending on the relative barometric pressure, is anywhere between 196 and 197F. So, I'm pretty much "stuck" at low brew temp parameters. My guess is that I'm brewing between 194 and 196F in general. This is a guess because I do not have the means such as a Scace to measure brew temp. I'm basing this guess on the group flush practices of my hx machine, and while I think my estimated temp is accurate, I may be totally wrong.

I was initially quite nervous about spending money on a "prosumer" machine due to the vast amount of references to ideal brew temps on sites such as this when those recommended temps are above the boiling point at my home. I then came across the Instituto Nazionale Espresso Italiano website and discovered that their temp requirements are 88C ± 2 (187 to 194F). That was encouraging to me, so I said to myself "WTF" and followed through with purchasing home espresso equipment. I'm glad I did. After some trial and error with different blends and improving my techniques/skills, I am enjoying espresso that is better than most of the local shops. Sorry about the little biography, but I wanted you to understand my approach.

It's confusing to me because I am not experiencing the horror tastes I've heard described of brewing at lower temps. Is there not still room for the lower brew temp in producing "decent" if not "great" espresso? When I go back to New York in a couple of months, I'll visit Gimme and 9th Street to see what I'm missing out on. Maybe I still need to discover a real cup of espresso.

Matthew Brinski

[another_jim]

The Italian standard calls for a measurement of the espresso exiting the brew chamber (basket in this case) using a thermocouple up the spout. This will be about 5C (9F) cooler than the temperature at the top of the puck. Therefore, this standard is equivalent to the 90C to 95C ones that measure at the top of the puck. The Italian standard is much easier when rating a cafe (which is what it is designed to do); the top of the puck standard is much easier when tweaking a machine. One should use whichever one is most convenient.

Your altitude problems may not exist. At the top of the puck, the pressure of the water is 9 bar, and permits any initial brewing temperature you like. According to Illy, most of the pressure drop is very close to the bottom of the puck. As long as your water is below the local boiling at that point, you're in good shape. Since the highest standard exit temperature is 90C (194F), even the highest regular brewing temperatures should be problem free.

Schomer famously coined the term the "Denver Effect" for the inability to get high brew temps at altitude, citing crema problems. This is a result ***nobody*** has replicated, despite many people making shots and posting about them from places at higher altitudes. He may have had an undiagnosed problem with his machine that day.

[Matthew Brinski]

Now I'm going to be experimenting again. Regarding the Italian measurement, it states "Exit measurement of water from the unit". I took this as brew water temp since it did not state exit measurement of "espresso" or exit measurement of "coffee". I understand that 9 bar will raise the boiling point, but my concern is the initial infusion which has yet to come under pressure. Now I'm going to go through alot of coffee tonight while messing around, thanks alot :) ... I'm sorry if this jacked your thread. I really appreciate your expertise.

Matthew Brinski

[luca]

Is the conventional wisdom wrong? Have blends changed dramatically? I'd be curious to hear what people think has happened to the lower end of the conventional espresso brewing range.

Interesting topic. My boss is using a very dark roast and recently installed a Cyncra (yay!). It came factory set at 203.5, which was way too high, so we dialled it down to 199.5F. We didn't do heaps of tasting below this, but the few shots that we pulled at 199.0 did have a faint lemon-peel quality and I vaguely remember pulling one at 198.5 that was quite unpleasant ... more investigation is probably warranted!

Cheers,

Luca

[cannonfodder]

As with most things, taste is perceptual. What is good to user a is bad to user b. I have had some good luck with a couple of low temp blends, and they were not dark roasts. I would say full city. A blend designed for more body and less acidity handles the lower temperature better IMHO.

Barry has a blend that works very well at the lower end of the temperature scale. He suggested I try something in the 198F range for his Decatur Street blend. I was getting the best cup at 199 on my machine, but my measuring device is not the most accurate. I would give it a ± of 2 degrees, but it works good as a reference point. I also had a home blend that worked well at the lower temps. I would have to go back and look at my log book to find it, but it was probably heavy on Sulawesi and Java, both of which are low acidity and heavy body beans.

Unfortunately, Barry's shop (Riley's Coffee & Fudge) is currently in flux, but hopefully it will back on line soon. I would recommend you (MattB) order a pound and try it out. I use to live in Denver but that was before my espresso habit. Compensating for the high altitude in baking was interesting, I am from Ohio.

Beauty shot of Decatur Street after the crema settled
.

[another_jim]

Yeah, but nobody's pulling anythng from 194 to 198, or 90C to 92.5C. We are also all setting our pumps in the lower half of the "official" pressure range, 8 to 9 bar; wonder if the temperature range is shifted if one goes up to the 9 to 10 bar range. When I first got the Tea it pulled at 11 bar on the panel gauge for ristretto shots, and I still ran it hot; so I doubt that's it.

[paradiseroasters]

I can't say i've ever come across a blend that required such a low temp. occasionally 197-198. but usually not lower. Most of my coffees are quite light and work best in the 202-204 range. The question I have is why? it is a generally accepted rule that lighter roast = higher temp. darker roast = lower temp. Does this have something to do with the way acids extract. I'm no chemist so i don't know about such things. What elements in espresso are temperature dependant for rate of extraction. do different acids have different temp ranges at which they most easily extract? what substances get extracted at the upper limit that prevents us from going any higher with some coffees without a negative effect on taste. conversely what doesn't get extracted at the lower limits that throws of the balance. Less sugars to round out the acidity? mineral substances that serve bonding agents for other organic substances? more importantly to baristas, how do we understand the hows and whys and compensate when working with a blend that requires a temp out of the range in which our machine is performing? example: if I was using a blend that performed best at 203 and my machine could only deliver 200 I would try dosing 2-3 grams less and use a finer grind to minimize the acidity, and maybe try a slightly longer extraction time.

another question how about freshness and temp.? would a blend 1 day out of the roaster be better at a different temp than the same blend 5 days out of the roaster?

[cannonfodder]

I run my Faema at 9 and my Isomac at 9.5 and my lever as hard as I want to pull. I think I get thicker, buttery shots at the higher pressures. Some blends don't work as well, but must work better IMHO. Some of my best shots have come from my lever machine at higher pressures. But they are all still in the 'accepted' temp range.

[another_jim]

[start of tooting my own horn] I looked for the relation between taste and brew parameters in 2002, after I got my Tea and could play with them somewhat. The only thing I found at the time, after a lot of searching, was a 2 separate notes in Schomer that in Italy the further south one went, the darker the roast, and the lower the pstat settings. This meant Italians tended to pull darker roasts at lower temperatures.

People were PIDing their Silvia's at the time, so this is one of those bits of info that was rapidly confirmed by everyone who tried it. I've been collecting tips on this ever since; and most are posted in my espresso guide here:
http://home-barista.com/espresso-guide-skills.html.

Shorter time and more lungo pulls also favor acidic, whereas longer time, more ristretto pulls favor bitters. So this too is a way of compensating if one cannot change the temperature [end of tooting my own horn]

I don't know much chemistry, but in general, every substance dissolves more if the water is hotter or one exposes the solid to it for longer. Also, in general, substances with low molecular weights dissolve more readily than those with high molecular weights. Coffee acids and origin aromas tend to be lighter than the bitter, roasty aromatics (see flavor wheel)

So my guess is that the acidic components dissolve more readily, and will be overrepresented when brew temperature is cooler or the pull is shorter. The bitter components dissolve more slowly, and require more heat and time. This means the acidic taste of cool shots is not from more acids, but from the changed flavor balance resulting from fewer bitters.

The thing that doesn't work in this theory is that really low temperature brews (toddy coffee and the recent aeropress) have no discernable flavor at all, except sweetish caramels. If the molecular weight idea is correct, these should be intermediate between the acidic and bitter flavors. They also predominate in the middle part of the espresso pull, which supports the molecular weight idea. But in toddy coffee, they are the only things to make it into the brew.

[Abe Carmeli]

Acidity and bitterness are relatively easy to compensate by a trained barista, however ashiness in a blend is usually beyond repair. I was working on Intelligentsia's Yemen Sanani today trying to escape an ashy aftertaste. I ran the entire temperature scale from 195 to 203 f, dosed 14-22 grams and ran shot time from 20-30 seconds and volumes from extreme ristretto to a double. Still ashy. I turned to pressure and ran it from 7-9 bars without much luck. I guess what's true about food is true about coffee: if you burn it, there ain't no maneuver in the world that will save your ass.

[another_jim]

if you burn it, there ain't no maneuver in the world that will save your ass.

Lots of grease is the traditional fix for burnt food. For coffee, aromatic distillates -- peat, fresh tar and creosote, cloves, etc -- will help a little because some ashiness is expected in association with these flavors. Try adding Sulawesi (which'll add body too).

This is the drawback of buying coffee based on light cupping roasts; sometimes you get a bean that can't stand the heat. Seems unusual in a Yemen though; they may have overheated the drum in your lot.

[MOSFET]

I had a Krups pump machine and then an Expobar. After measuring a roughly two degree intrashot temperature in the Expobar I tested the Krups, mostly for fun. The temperature reduced from about 200 to about 185 during the shot. I thought this was funny, but I'll tell you I never had a horribly bad shot out of the Krups. I had plenty out of the Expobar. The Krups produced milder, thinner shots that were almost always decent. Never as extremely good or extremely bad as the prosumer. Just some experience that stuck with me. Another experience on this was during a long conversation with an old Italian barista who said the Italians like it cooler than the Americans. I asked how cool and he said about 180. I was not sure I believed him but it stuck with me.

Keith

[another_jim]

... I tested the Krups, mostly for fun. The temperature reduced from about 200 to about 185 during the shot... The Krups produced milder, thinner shots that were almost always decent.

Most Krups also have restrictors that thin out the shot.

[another_jim]

... I tested the Krups, mostly for fun. The temperature reduced from about 200 to about 185 during the shot... The Krups produced milder, thinner shots that were almost always decent.

Most Krups also have restrictors that thin out the shot.

[SL28ave]

You're gonna love this

192 F is the new recommended brew temp for Terroir's North Italian roasts (probably the lightest espresso roast in the US). We may refine this position over the next few weeks, but I'm fairly certain that this will be the new standard.

Using a Scace Thermofilter (accuracy verified by a second Scace Thermofilter) on a La Marzocco we've come to this conclusion.

[another_jim]

You're gonna love this

192 F is the new recommended brew temp for Terroir's North Italian roasts (probably the lightest espresso roast in the US). We may refine this position over the next few weeks, but I'm fairly certain that this will be the new standard.

Using a Scace Thermofilter (accuracy verified by a second Scace Thermofilter) on a La Marzocco we've come to this conclusion.

192F on a roast most consumers nowadyas would think too light for regular brewing? You guys are going to become the official "american specialty coffee contrarians" if you go on like this!

I'll have to try it and see if an old fuddy-duddy like me can survive the taste

[SL28ave]

Actually, give me a week to play with this some more. I want to follow the WBC protocol exactly. Will get back on this!

[jason_casale]

I believe there are still some espresso cafe darte that require lower temps. 195 to 198 is right for most of their blends. But they may be extracting at higher brew pressures and using darker blends therefore requiring lower temps. Your temp of course will be higher using darker blends if your pump pressure is relatively low say 8 to 8.5 bars at sea level. Because of the cause and relation between pump pressure and temperature. Darte works well for me at 198 pid and 8 bar. If I increased my pump pressure to 9 bar the temp may need to be 195 to compensate for the higher brewing pressure. Make sense? Thanks Jason

[Abe Carmeli]

Is the conventional wisdom wrong? Have blends changed dramatically? I'd be curious to hear what people think has happened to the lower end of the conventional espresso brewing range.

Lately I've been brewing most blends and S/Os at 198-199f, and that includes the famous Bale Kara Yirg from Paradise Roasters. It is a combo of two things in my experience: the roast profile; I use a long roast ~ 19 minutes with a slow ramp-up to first crack. That profile mellows down the acidity. All my roasts are stopped at or before the first snaps of 2nd crack, so they are all city+ to light full city. The other contributor is the M3 grinder. It allows for lower brew temperature on acidic coffees. (even grind, less fines & perfect distribution).