Hi, I'm new here and i have a Livia 90 with Mazzer mini, and i'm trying to make a good shot with the
combo, i tried Malabar, Tanzania, and columbia, and no matter what i did the shots are bitter and kind of sour, the beans are about 2 days old..
they are slightly better with the Columbia roast, but it's still sour/bitter...
i have my grinder set to a 25 second 2 ounce shot and i weighed my beans before grinding at 16 grams,
can anyone please tell me what to try next, i'm thinking it could be the water temperature or maybe even the tamping process, thanks, all in advance...

I have the same machine. I:

1) let the Livia come to temperature for about 40 minutes
2) grind into the basket
3) tamp (with the basket out of the portafilter)
4) Pull the portafilter and run the extraction water over it for three seconds after the water stops boiling
5) Pop the basket into the portafilter
6) lock
7) pull the shot

I'd say that if you are getting both sour & bitter than it sounds like a distribution problem. Sour is usually indicative of an underextraction and bitter of an over extraction. Try the WDT, Stockfleths, etc. to ensure an even distribution of coffee in the basket. And a level tamp. Even if you are dosing and distributing well, if you impact the screen on your machine, you could be disrupting your puck and causing channeling which coupled with a finer than necessary grind could give you a proper extraction time, but leave you with bitter/sour shots.

If only fixes part of the problem, it could be a temperature problem as well. Sour shots can result from a temperature that is too low. Using a thermometer pushed through an inverted paper or styrofoam cup, you can guestimate the brewing temperature by placing the thermometer directly under the shower screen. Typically, people aim for a temp between 195-205.

But being both bitter and sour sounds more like distrubution...

Just to be 100% sure, as you didn't mention anything about it...

Are you performing a cooling flush before your shots?

If yes, please excuse me.

If No, allow me to explain...

The Livia 90 and Mazzer Mini, together along with fresh coffee from an Artisan Roaster(See, List of our favorite Roasters for where to find high quality coffee all across the country) make for a nice, plenty capable setup.

The Livia is a Heat Exchanger machine, which means it operates differently then machines like the Rancilio Silvia and the Gaggia Classic. In short, you will need to preform a cooling flush before you pull your shots, so that you get a proper brewing temperature. For the best article/How-To on how a HX machine works, and how YOU operate it, see Managing the Temperature of Heat Exchanger(HX) Espresso Machines

You mention the origin of the coffee, but not the roaster or roasted on date. You mention it is two days old, if it is two days out of the roaster it should probably out-gas more, if the bag was opened two days ago, the coffee could have been roasted two months ago. We need more information to lend a hand, could be temperature, could be distribution, could be stale coffee or roasting defects, doubt it is the tamp unless you are really crooked. This is where a bottomless portafilter pays for itself, diagnosing issues. But an off the cuff guess, your temperature is to high and you are getting channeling. Also, not all single origin coffee makes good espresso. They tend to be much less forgiving, you may want to try a blend tailored for espresso.

Thanks for the help, i think that first guess was right, i need to work on tamping and distributing,
sometimes i notice i wasn't tamping straight so i try to straighten it out by leaning the tamper the other way,
is that something you recommend me doing? or is that a no no?
i am pulling shots that were sweet, but some that are light with no body, and kinda sour,
i am doing about a 2 ounce flush about a minute before i extract the espresso,
the beans i was talking about were actually roasted a 2 days before,
also there might be a possibility that the machine is a little on the cold side, but i assume primarily i need
to work on distributing, but i hate doing it with my finger, especially if i make someone else an espresso,

rattaps wrote:i wasn't tamping straight so i try to straighten it out by leaning the tamper the other way,
is that something you recommend me doing?

Trying to correct a canted tamp after applying pressure usually makes matter worse. It breaks the puck/basket adhesion and creates fissures in the puck, increasing the likelihood of channeling. It is a major "no no".

rattaps wrote:i am doing about a 2 ounce flush about a minute before i extract the espresso

Your rebound time sounds too long, unless the pressurestat setting is really low, or you're overflushing (not likely if only 2 ounces).

rattaps wrote:i need to work on distributing, but i hate doing it with my finger, especially if i make someone else an espresso

Assuming you practice good handwashing hygiene, there's no reason to worry, especially considering the coffee is subjected to water near the boiling point at 9 bars of pressure.

So what should I do after I didn't tamp straight? Can I loosen my grinds and try again? Wouldn't hurt practicing a couple times, if that would be ok
Im doing about a 2 ounce flush, plus im preheating my cup, so you could say its a 4 ounce flush about a minute before, providing the hot water faucet is also considered a flush.
I just made a shot and i paid special attention to distributing, just packed it slightly and tamped it, and there was absolutely no channeling and but the shot was a little too fast even though there were some fine grinds in my cup, does that indicate i need to grind more coarse and tamp harder? I think i need a bottomless portafilter. Anybody agree?

The reason Dan said what he did about your flush is that on HX machines, the flush should happen immediately before you pull the shot (depending on the machine of course) as the temperature in the HX will start to rise after your flush.

Try this experiment. Using a digital thermometer, flush two ounces into a cup and temp it. Wait one minute and repeat. Chances are they will be the same temperature, so if your machine is running hot then your one minute before flush doesn't accomplish what it is supposed to. A high temperature can also cause a faster extraction. Something to think about. Also, the hot water spout (i believe) pulls from a different reservoir than your group head, so you should not count that in your overal flush routine.

Don't worry about using your hands in the coffee...this is how it's done. (for the most part) Walk into any one of the highly respected cafes talked about on this site and you will see baristas using their fingers and hands to level and distribute the coffee. If your coffee is tasting okay, but running a little fast, I would recommend that you a) use a little more coffee or b)grind a little finer. You do say that your shots are sweet, but a little sour. This sounds like classic underextraction. The above should help you remedy the situation. IF your machine is running cold, this could also cause the problem. But let's tackle the easy to fix problems first.

Tamping harder should have a negligable effect on your overall shot time.

JmanEspresso wrote:The Livia is a Heat Exchanger machine, which means it operates differently then machines like the Rancilio Silvia and the Gaggia Classic. In short, you will need to preform a cooling flush before you pull your shots, so that you get a proper brewing temperature.

I have a Bezzera BZ35, which is similar to the Livia 90 (also made by Bezzera). Both of these HX machines do not have a thermosyphon to heat the group. Instead they use a thick chunk of brass to conduct heat from the boiler to the group. I have found that the group on my machine is very slow to warm up, runs a little cool, and actually needs a very short heating flush rather than a long cooling flush. The heat exchanger volume is also very small and is rapidly filled with cold water if you flush too long. I performed some temperature tests using a portafilter thermocouple and found that a two second flush followed immediately with the shot seemed to deliver the best temperature stability.