hello,

i want to start a topic on pre-infusion. and secondary, it's relation to other parameters, too.

i have acquired a broken pavoni eurobar, had it fixed and it got back yesterday. i have been reading many, many threads, how-to's, faqs, and so on. i am struggling to get great crema, great taste, and good body on this machine (of course i have tried many things and will try many more) and there are so many parameters to fiddle with! (but i've made a good amount of very drinkable cups, after i managed to get the grinder at a decent setting)

the one parameter that mystifies me the most, is pre-infusion. i do understand what technically happens, you pour hot water at low pressure (roughly around 1 bar, i suppose) over the coffee, before you pull the handle to create more pressure.

i've heard people who do not include the pre-infusion time in the espresso extraction range (around 25 secs). this seems fairly odd, since the water is in contact with the coffee and the chemical process called extraction start taking place, though it might be at a slower rate.

i have had the best results so far using a rather fine grind, to get the right sweetness. i am measuring the amount of coffee with a 0.005 scale, very light tamper, but the machine pulls too heavy if i do not pre-infuse for a rather long period, say 15 seconds. which is half the total extraction time! if i let it run longer, there will be too much sourness, and the crema will be too light a color, too.

a coarser grind will not give enough sweetness, too bitter and intense, a little harsh.

the crema layer is on the thin side, say 3mm after a minute. and i struggle to get enough body. it's too watery in texture, not creamy enough.

i am not sure where to go next, i could use some help at this point. any suggestions are welcome, and please give me some experienced input on the pre-infusion thing.

thanks a lot!

best,
gido.

The La Pavoni is super fussy about grind. Also, you need to make sure you have good/fresh beans. I use a Kyocera hand grinder (which I have modified slightly). I usually grind +/- 1 click from where the burr just touch and stop rattling around (when you shake the grinder). This seems to produce the best results.

From there, fine tune with grind and tamp.

As far as pre-infusion, I usually do about 5 seconds. Just lift the handle, let the water flow into the group head and then count to 5. Usually I start with a moderate pressure (about half normal) until all the droplets of coffee form.

Using a naked portafilter is extremely important also. I also use a custom Reg Barber tamper that is nearly an interference fit with my basket. It's 49.6 mm and I have a 49.7 mm one on order. Having the naked portafilter, in order to diagnose what's going on, is critical. If you don't have that, you are largely operating in the blind as far as whether your grind/tamp are dialed in or not.

The other thing is temperature. I'm currently in the process of PID'ing my La Pavoni and the reason for this is because I have found that temperature control on the La Pavoni (at least the older two switch model that I have), leaves a lot to be desired. Nevertheless, I have pretty good results by heating the machine up, then turning it off about 30 to 60 seconds before pulling a shot. I also have a modified adjustable pressure regulator, which helps trim things out a bit as far as how fast the pressure dies down (or not). Basically, I turn the power off while grinding and try to pull the shot right when the stream is dying down (but when there is still enough pressure in the boiler to push the water into the group head). If I miss it by a few seconds, then I kick the machine back on the high (i.e. steam) setting for 2 or 3 seconds - just long enough to push some water into the group head.

As far as shot time, I usually go more by pressure required on the handle and the color of the extraction. Pressure should be moderate, not super crazy (although you can get a very good shot by nearly choking out the machine and going for a long, 60+ second shot). Mainly, however, shorter pulls, which require less pressure yield better results. 20 to 30 seconds is about right. I just cut the flow off when it goes blond.

Another thing that is helpful is to pull the shot and taste sections of it. I will sometimes pull a shot for 1 or 2 seconds, then taste it (halting the extraction for a second), then continue. I just stick a little spoon under the flow and test it along the way. This is helpful as far as seeing where the good part of the flavor is occurring (and from there, you can cut in/out the shot depending on what flavors you like, etc.).

Once you get a feel for your machine, you should be able to dial it in more by sight and feel, as opposed to any specific extraction timing.

Again, having a good grinder is very important. The La Pavoni is extremely sensitive to grind.

Ray

You could also add a pressure gauge (like a pav pro). I surf the temp a lot using the gauge and the on off switch......

thanks for your reply. i have a mazzer mini. it's a great machine, and that part should be covered.
i buy fresh beans every week.

are there any tricks to get more body/thickness/creaminess to the extract?
i've read in a review that the eurobar is great at this, but so far the texture has been rather too watery.

zubinpatrick wrote:You could also add a pressure gauge (like a pav pro). I surf the temp a lot using the gauge and the on off switch......

thank you for your answer.

this machine does have a pressure gauge, but it only gives you the pressure from the boiler, not the pressure you are given through the lever pump.

what does high vs low pressure do? from what's i've come to understand, too high pressure gives more intense flavors, while lacking sweetness to balance it, which could be (a part of) the problem. while too low a pressure should do the opposite, ie produce bland flavors.

the pressure valve indicates between 0.8 and 1.0 bar. i will try to make some espresso at 0.8 bar, with longer pre-infusion, to lower the pressure. see if i can get a sweet cup this way. if this works, i can look further for the right balance.

still, how does one get a thicker body?

and i hope someone will explain the ins and outs of pre-infusion to me.

You don't say what type of coffee beans you are using, which could help the good people here give you more good advice. Different beans work better at different temperatures, which is really what the comments about boiler pressure refer to: the higher the pressure, the higher the temperature of the water coming out. And of course different beans have different flavour profiles.

But some of this could still be to do with the freshness of the beans. Where are you buying them from? Fresh supermarket beans are not in fact fresh......

But assuming you are buying from a quality local roaster and using beans just a few days after they were roasted....

From what you write, pulling at 0.8 could be a good idea.

But I think you may need to do some more experimenting with the grind and dose. You say you are weighing the dose. What dose are you using and what volume of shot are you pulling?

Something there is not right. Both your preinfusion and extraction times are long and your comment that "the machine pulls too heavy" if you do not preinfuse for 15 secs indicates you could be grinding too fine or dosing too high, especially since you write you are only tamping lightly.

What do you mean by "the machine pulls too heavy"? What does this feel like?

Sorry to sound like the Spanish Inquisition, but without more information it will be difficult to give you reliable advice that helps you get the sweetness and rich mouthfeel you are after.

Cheers

Mike

hello mike, thanks for you reply.

i am using beans from a local roaster. they have a website, but it's in dutch. http://www.brandmeesters.nl/koffie.html they used to have the roating machine in the store, but now that they've expanded (3 stores) they moved the roaster to a different location, but it's still decent fresh stuff.

i've purchased medium roast and a dark roast types. the flavors where different, the problems stayed the same.

i have come to trying a fine grind (and less coffee) to the point where i almost suffocated the machine, from advice in this http://www.home-barista.com/espresso-gu...blems.html article. i am after single shots, because that's the amount of coffee i get naturally from a 25-30 seconds pull. i've been using 6 - 7 grams of coffee. around 6.5 seems to be the best dosage. i do use a double portafilter, i don't have the single one. i do get thin mousetales when i pour a shot.

when i say 'too heavy' i mean i have to use a lot of power, and it will go very slow. i won't be able to go down in 25 seconds. i realise this is not right. it seems a longer pre-infusion makes it easier to go down.

from reading all this, i would jump to the conclusion, i need a much coarser grind. but when i try that, the coffee will not taste good, no sweetness, too bitter, a bit harsh and a bit sour. the body does enhance a little, but not that much.

i am going to try the technique used in this video Using the Olympia Cremina -- The Movie (Video) with short pulls in the pre-infusion, but if that doesn't work i don't know what to do anymore.

best,
gido.

Bad news all round, I'm afraid, but not that bad.....

Depending on how long it takes for the roaster to distribute the coffee to their outlets and how long it waits there before it's sold, you could well be buying beans that are already past their best before you even get them home.

Try a reputable "online" roaster who can ship direct. If you don't know of any in the Nwetherlands, there are several in the UK who will ship to the EU (Hasbean, Londinium, Square Mile, Union.... strictly in alphabetical order!)

I also think you may simply need to get hold of a single basket. The Eurobar has a reputation for being a fairly tolerant machine (Pavoni Eurobar will not heat), which is probably why it's not simply gushing on a part-filled double basket. Rather than complicating things further with Fellini partial pulls, I'd try keeping the dose where it is and maybe grinding just a little bit coarser, not "much coarser" as in the past, preinfusing for less (say 6-8 seconds) and giving a nice slow, firm pull. Don't worry if it takes a little longer than 25 seconds....

Drop Doug at Orphan espresso a line, he may well know the size/part number of single basket you require and may even have one in stock. Or of course La Pavoni should be able to help. I recall they are the same as the pre-Millennium Europiccola/Professional models, which makes them a 49mm diameter design, but my memory could be playing tricks with me.

My gut feeling is that a fresher coffee and single basket will cure your woes....

Cheers

Mike

Jeroen Vriesendorp ("HV" to his old alt.coffee friends) is an encyclopedia of all things coffee. His list of European roaster links might be a good place to start, since he keeps on top of the local coffee scene. http://home.planet.nl/~rjeroenv/links.html#8a1

gido wrote:thank you for your answer.

this machine does have a pressure gauge, but it only gives you the pressure from the boiler, not the pressure you are given through the lever pump.

what does high vs low pressure do? from what's i've come to understand, too high pressure gives more intense flavors, while lacking sweetness to balance it, which could be (a part of) the problem. while too low a pressure should do the opposite, ie produce bland flavors.

the pressure valve indicates between 0.8 and 1.0 bar. i will try to make some espresso at 0.8 bar, with longer pre-infusion, to lower the pressure. see if i can get a sweet cup this way. if this works, i can look further for the right balance.

still, how does one get a thicker body?

and i hope someone will explain the ins and outs of pre-infusion to me.

What I'm trying to point out is that pressure in the boiler = it's temperature. So if you have higher pressure in the boiler the water will be hotter during the pre infusion and the pull. So I'm more talking about the water temp as a factor in the flavor of the shot. FWIW I use the pre infusions as a way to monitor my tamp/grind. I like no drops for at least 10 secs but then when I pull the lever down I want the flow to start immediately, for me this means the puck was fully saturated but tight enough.....
While we are on the subject of temp surfing I will let you in on my nasty secret. My Pav Pro is set to idle at 1.25 bar! This is way too high/hot for a Pav but my SO likes milk drinks and a Pav steams quite nicely at higher temps (lame at 0.8 ), so I turn it off at .8 pull my shot, pull the boss's shot (maybe turn on for a moment to keep the temp up) then while pulling the shot leave it on to bring up the pressure for the milk.
This works for me, what works for you will be whatever you discover. As you have seen there are a bunch of variables, you play around with them 'til you get it right. IMHO most important is good fresh coffee, 2nd is grinder, 3rd is machine /technique. Pre infusion fits into the last group, it plays a part but won't save you from problems in 1 and 2....I wish you , and everyone, good luck with #1 & 2. (childish humor, too many kids around)