sunnynights123 wrote:Hi everyone,

I was hoping someone could give me some advice. I have been trying to dial in my espresso machine (Lelit Bianca) today and having trouble finding the sweet spot. I cant find a grind size that it either not too sour to too bitter. Is there something else i can try?

Equipment:
Niche grinder : new / calibrated
Lelit Bianca : temp 93dc, no pressure profiling (i am not touching the profiling paddle). Always using 18g dose in the naked portafilter

{snip}

As you can see the sweet spot sits between 20 and 21 grind size. The inconsistency might be totally because i am new at this!

Any tips on what if there is anything else i could try? I noticed that for most of the shots the pressure goes up to 11 - 12 bar?

Don't give up.. you're on the right track. As a newbie... trying to pull a great tasting shot can seem like it may never happen. I remember going through at least 5 pounds of coffee when I got my first espresso machine before I managed to a pull a drinkable shot. Even for an experienced barista... getting a brand new machine and new grinder at the same time can be a bit of a challenge before they can hone in on a great shot. Patience is key. Eventually you'll sense the adjustments you need to make to improve your shot but that comes with time and experience.

Don't forget there are a myriad of variables. The coffee, coffee blend, coffees age, the grind, your prep - to tamp or not, the water - to soft or too hard, ph levels, brew temperature, brew ratio, pre-infusion (or not) extraction time, extraction amount... just to name a few. A drastic change to any one of them can throw off a shot. TIP: The best tip... dont change multiple factors each shot. Change "one thing" and pull a shot - e.g, don't change the grind and dose amount at the same time.

The fact that you honed in on a 18gr basket is great. Changing out basket and dose amount every other day only makes for a moving target. You also honed in on a temp of 93C which is good rather than bumping the temp up and down when seeking nirvana. I also have a Bianca and almost exclusively use a 18gr PF basket (a VST 18gr, not the one-size-fits-all that came the Bianca.) My Bianca happens to be set at 94C, but keep in mind the brew temp setting is dependent on the coffees roast level... as briefly covered in this video

Also, make every attempt to ensure your pre-extraction prep work is exactly the same every time. (e.g. same amount of weighed coffee, same leveling technique level, same tamp) I personally use a scale to weigh each 18gr dose, a leveler- followed by a tamp with The Force Tamper, In this way I know my "puck preperation" part of the equation remains consistent from shot to shot (one less variable) FYI: I use the Flat Base on my tamper not the Ripple base shown in this video.

Like you I also own a Niche Zero. As mentioned by sunntynights123 it takes some time to "season" the burrs of most new grinders. When I first got my Niche I purchased 3 pounds of outdated supermarket bin coffee beans (marked down for a quick sale) ... then proceeded to grind the entire lot and throw it out. If I had to guess I'd say I went through another 4 to 5 pounds of during my normal daily routine of making our morning espressos before the grinder settled into a groove where I could depend on consistent shots.

Be aware the Niche responds quicky to small changes. It's best to move the grind setting ring in half degree increments and try another shot. Moving it two dots at a time is too aggressive. Also, grind for flavor... not extraction time. Some people make the mistake of adjusting their grinder so a shot will extract in exactly 25 seconds then move on to another variable. Normalising your grind is the perfect place to start but don't fall victim to the old 25-30 second shot rule.

NOTE: Also like you... I noticed my Bianca was hitting 11-12 bars during shots. First thing I did was adjusted my pump pressure to max out at 10bar by following this video. FYI: I pull 99% of my shots at 9bar via Biancas flow control but figured 10bar was a little higher just in case I ever felt like experimenting.

Its a learning curve. Stick with it. If you haven't already discovered it, check out >Espresso 101: How to Adjust Dose and Grind Setting by Taste.