Dear List,

Let me first say thanks in advance. I have owned my La Pavoni Professional 16 cup since 1999, it is a gen 2 I believe (1 switch and small portafilter).

It's back from the dead (2 years) and its making horrible shots.

I have replaced the various gaskets in the group over the years (it moves smoothly up and down with ease). It developed a slight boiler leak and the heating element shorted out, ordered a kit from OE and I couldn't get the heating element out of the boiler, it was deformed and like a ship in a bottle I have no idea how they got the thing in there. I used blood, sweat and a bolt cutter to remove it and shipped the machine off to Stefano's repair shop to install a new lower gasket, heating element, pstat all to the tune of way more than I wanted to spend.

So, I went and purchased (in Los Angeles) some Blue Bottle Dandy Blend (Handsome Roasters carry over), 8 oz for $12 usd. Date on the package was 3 days ago, so its fresh. I dusted off my Gaggia MDF grinder, used a black piece of tape on the shoulder of the group to use an IR thermometer to read temp. The temp read somewhere about 200F, the grinder was set anywhere from 8 to 4, it looked fine to me. I would blow off steam and then do a shot, not good. I found a pickle jar thread on bleeding out air in the system. I have bleed out the air but the lever is still mushy ( I don't get any bubbles from the steam want lifting the lever). In fact when I give it a firm tamp (30 pounds via espro calibrated tamper) and I raise the lever to perfuse for 5 seconds and I lower it I hear a gurgling sound. I have tried the la paving fellini move up and then down again and nothing. I would pre infuse for 5 seconds and try for a 25 second shot pull. I get bitter coffee without really any crema at all. The puck is nice and dry. I am using 13-14g of coffee in the double basket. Water is tap poured through a Berkey which doesn't remove any minerals. Friend owns a fancy total dissolved solids meter. I could try distilled water but I think that it tastes funky with coffee????

I would love to get some feed back and thoughts from good local coffee in LA that isn't $24/pound to group head temp to pulling. I swear 5 years ago I could make a nice shot but I can't seem to and I am 7 shots in without any luck. After about a DAY of reading I am still pulling sink garbage sadly. My apartment does smell lovely. I am happy to make a video if need by on my 'technique' or lack there of.

Thanks,

Ken

Hi Ken,

First make sure your pressure gauge reading somewhere between 0.7 to 1 right before you lock your portafilter.
Second, try pulling a shot without tamping at all to find out if your grind is too coarse or too fine. If you are able to get better crema without tamp then set your grinder to a coarser setting and tamp lightly. Repeat increasing tamp amount/coarsening grind setting until you find the sweet spot. If step 2 yield no crema at all, then do the right opposite, try grinding finer, tamp harder etc.
If these do not work at all, then change the coffee and try again before moving onto machine related problems.

Below find 2 pictures, same coffee, same grind, same amount, same everything, one is leveled and other heaped before tamping. The change was dramatic both in looks and taste. I was never able to get decent results with that particular coffee which was roasted by a 3rd wave Turkish roaster (yes they sell it as an espresso blend) unless I prepared it in a certain way, which I reached to conclusion by lots of trial & error, then to make sure I went through another lb with same coffee, same roaster, just heaped vs leveled




On the other hand, with this particular coffee from another roaster every shot was tasting great no matter how I prepared it. In fact, the shot in the picture taken by a friend of mine who absolutely has no experience with coffee making and do not like coffee at all. She was so amused with pavoni, wanted to try her hand at it and literally nailed it at her 1st shot. So, short version, source of your troubles could be related to the coffee you are currently using.

I always recommend that people always follow a rule that I have followed for a long long time: Never change more than one thing at a time, because when one changes two or more things, there is no way to tell which change improved the situation!

My most commonly used espresso machine is similar to yours, 1999.

For a long time I have always roasted my own coffee. I have a Nesco roaster, which is consistent, but which does not permit much control over what it does. I like its results, so hence it is used a lot. The other technique I use is the "atomic cooker wok technique". There are available propane outdoor wok stoves that at full heat put out around 35 to 40 KW of energy. This is greater than my brother's furnace, and he lives in Wisconsin! One needs a big enough wok and some practice to do this, but the results are fantastic after that practice. It obviously must be done outdoors!!! One needs to know just where to adjust the heat on these things. Too high will cremate the coffee in seconds! Green coffee is stable for long storage, so one can keep a large supply on hand of many different coffees. Another advantage of this is being able to control the roasting process.

I have never used tap water. Our water here is highly erratic in composition. Sometimes it is so hard that I have to descale pots and pans after cooking vegetables. I normally start with distilled water and add sufficient KHCO₃ to make it about 1.0 mM in bicarbonate, that is 100 mg/litre. This prevents scale and enables control of acidity. Some may want more some may want less bicarbonate than I use. Some add other things to distilled water to get the same effect, but most other things one would want to add are already present in high concentrations in the beans. (The Na content of beans is low, and using NaHCO₃ adds Na which can create flavour changes I do not want. Others may like those flavour changes?) Compounding water this way keeps another variable from being out of control. When descaling is never necessary thick copper oxide coats form on the brass and copper surfaces which makes them very stable. This avoids getting a lot of copper into the espresso as well because these oxides are extremely insoluble!

Remember consistent grinding is of ULTRA importance. Much has been said in HB's grinder section on this.

I have described on HB posts before how I make shots, but basically what I do is put the loaded portafilter and the cup to the right of the machine. With my left hand I raise the lever until a bit of steam is released, lower it a tad, and then with the right hand immediately snap the portafilter in place. I put the cup in place and raise the handle all the way. I bring it down just enough to make a few drops of espresso appear, raise it all the way, wait a second or two and make the pull. This avoids pulling air through the puck and cracking it, and also prevents spongy shots. It makes the shot size absolutely the same all the time too. I always wait 3 minutes after the boiler and group bleed before making the first shot.

Also be sure the machine is clean. Look into the boiler with a light at least once a week. The group gets filled with "gunk" that can become rancid and produce off flavours. I tend to disassemble the group and clean it thoroughly about once every three months.

Try pulling the shot when the side of the group rises to 76C (169F). Weigh your dose (try 11 grams). Grind should be fine enough that you really have to lean into it when first starting to pull the lever down. Maintain a constant lever velocity (ie, less pressure as you reach the bottom). Optimize for taste, not crema production.

Thanks to all the replied here. I have been busy and I wanted to do some proper testing. I really appreciate all your tips from cleaning to lever pulls, temps etc.

I have uploaded a few videos here...

https://flic.kr/s/aHskdX9FsL

Jonr, please see this photo where I read the temp. I typically see 200F and sometimes more. I have tried to bring up a mug of cold water and submerge the group to lower the type down to 170 or so but it heats up very quickly. I have been using 11g of finely ground locally roasted coffee.

Rpavlis,

I purchased http://www.amazon.com/gp/product/B0064G ... ge_o01_s00 and I would love to know how much to add to a fresh gallon of distilled water. I have a scale that can measure 1 gram. I feel like my MDF is grinding pretty consistent.

Kahvedelisi, Very interesting and thanks for taking photos! I tried both ways and there wasn't much of a difference.

For the 3 videos I varied my grind setting in 1 step. I would blow off steam and wait for the machine to bubble up and the heating element to switch on. I would load a 30 pound tamped puck and lift lever (I tried it both ways and moving it up before loading helped a lot). I would wait for the rush of water when the lever was up high and I would do a 5 count. Then I would lower the lever and try for a 30 second pull. I did my best. Off camera I have weighted the shot and it was somewhere around 25-30 grams. I know that a 1:2 ratio would be 11 grams of coffee to 22 grams of espresso. After these videos I did sample some 22 gram shots. I have tried two types of local coffee with the machine and I am wondering if it is just running too hot. Either way the shot is pretty bitter to my pallet.

Thanks again for looking.

Ken

To me 1.0 mM potassium bicarbonate in pure water provides about the best flavour. It is also near ideal for lack of corrosion with copper and brass. It is near the concentration of bicarbonate in slightly hard water.

Here is the easiest way, as far as I can see to get pure water to this concentration of bicarbonate: The molecular weight of potassium bicarbonate is 100 g/mole. It is more soluble than sodium bicarbonate, so it is easy to make a 10% solution. Find a measuring cup that will measure in millilitres, most modern ones do. Weigh out 10 grams of potassium bicarbonate. Put this into the dry measuring cup. Add distilled water and keep stirring. The potassium bicarbonate will slowly dissolve. When you get up to about 90 mL stop adding the water and keep stirring until the solid is mostly dissolved. Now add distilled water up to the 100 mL graduation. Find a bottle that is big enough to hold this volume and put the liquid in it. Label it 10% potassium bicarbonate and put it away for storage. This is enough to make a LOT of espresso brewing water.

I have a neat little glass measuring cup that measures 150 mL, I got it from a department store, I forgot which, but it is very ideal, because it is graduated ever 10 mL, and because it is easy to stir using a small spoon or chopstick.

Each millilitre of the 10% solution described above now contains 100 mg of potassium bicarbonate. Distilled water is sold in various sized containers, in the US it may be sold in US gallons, which is 3.7 litres. You need to add 3.7 millilitres of the potassium bicarbonate per 3.7 litres.

You may be able to find an eye dropper that is calibrated in millilitres. You can come fairly close by estimating that each 20 drops is one millilitre. Then you would need to count out about 75 drops. Pet stores may sell small syringes for feeding sick or baby birds. The ones the size for cockatiels and similar birds are graduated, and measure up to 10 mL. They are wonderful for this. They are plastic, and instead of a fitting for a needle, there is a curved plastic tip to insert into the bird's mouth. (Much larger ones are available for birds like macaws and large cockatoos.) You may also be able to find small pipets, you would need a 5 or 10 mL one.

You can also use measuring spoons. You would want to add about 3/4 teaspoon to 3.7 litres of water. That is less accurate, however.

It is MUCH easier to keep a stock solution than to try to weigh it all the time.

The real wonderful thing about handling the water problem this way is that you can control the bicarbonate concentration. For dark roast you may prefer lower amounts of potassium bicarbonate. If you use straight distilled water you will find that the espresso is likely to be overly acidic, and thus have a sour taste. Coffee has very very low concentrations of sodium in it, and a LOT of potassium, and a quite a bit of calcium and magnesium, there is FAR more calcium and magnesium in the coffee beans than in the hardest water. Brewers use potassium bicarbonate, because they do not want to add alien things to their product that can cause flavour shifts. Coffee beans are 2% potassium!!! By using potassium bicarbonate, you do not change the balance of cations that are in the coffee.

You can test and add varying amounts of the stock solution to find the best flavour for the beans you use, and for your taste.

rpavlis,

Thank you very much for that extremely detailed explanation!! I'll try this and see how it adjusts the flavor. It will save me the descaling issues with the hard water in Los Angeles and help me in the future.

I measure temperature a little higher on the side of the group - with the gun held tight to it. The machine is cold, you turn it on, then it takes quite awhile for the side of the group to hit 76C.

I'd grind fine enough that it takes ~30 seconds from the first drips. I use a very light tamp with no knocking or nutation.

Jonr,

Thank you. I'll try to measure it up higher. I use that espro 30 pound tamper but I can try variations not pushing down that much.