The Perfect Espresso: A Precision Brewing Guide

Espresso is the ultimate test of precision. Under 9 bars of pressure, extraction happens in seconds, and every variable, dose, grind, temperature, pressure, must align perfectly. Whether you're using a traditional machine or the innovative 9Barista stovetop system, here's how to dial in exceptional shots consistently.

What You'll Need

For Traditional Espresso Machine:

• Espresso machine with 9 bars pressure
• Portafilter and basket
• 18g coffee beans (for double shot)
• Burr grinder
• Tamper
• WDT Tool
• Scale with timer

For 9Barista:

• 9Barista brewer
• 16g coffee beans
• Burr grinder
• Tamper
• WDT Tool
• Heat source
• Scale

Grind Size: 250-400 Microns

Espresso demands the finest grind of any brewing method—aim for 250-400 microns. This range allows proper resistance for 9 bar pressure while permitting 25-30 second extraction. Too fine (below 200 microns) causes channelling, excessive pressure, and bitter, over-extracted shots. Too coarse (above 450 microns) produces fast, sour, under-extracted shots with no crema.

Starting Point: Begin at 325 microns for a balanced extraction with good body and sweetness.

Fine-Tuning: Espresso is extraordinarily sensitive to grind changes. If your shot pulls too slowly (over 35 seconds) or tastes bitter and harsh, move coarser by 10 microns (try 335). If it pulls too fast (under 20 seconds) or tastes sour and thin, go finer by 10 microns (try 315). Under 9 bars of pressure, these 10 micron shifts create clearly noticeable differences in flow rate and flavour.

Advanced Dialling: Once you're close to your ideal shot, 2-5 micron adjustments genuinely matter. This isn't theoretical, at espresso fineness under high pressure, a 3 micron change can shift extraction time by 2-3 seconds and noticeably affect sweetness, body, and balance. This level of precision is where great espresso happens, letting you fine-tune for each coffee's unique profile and achieve that perfect 25-30 second extraction with rich crema and balanced flavour.

Bean Variables: Light roasts are challenging but achievable at 300-325 microns, often requiring higher temperatures (95-96°C) and careful channelling management. Medium roasts shine at 315-340 microns, producing classic balanced espresso. Dark roasts work best at 340-375 microns to prevent bitterness and over-extraction. Document your exact settings, repeatability is everything in espresso, where a few microns separate mediocre from exceptional.

Traditional Espresso Machine Method

Prep: Ensure your machine is fully warmed (15-20 minutes). Purge the group head. Your portafilter should be hot to the touch.

Dose: Dose 18g of coffee into your basket. Distribution matters, use WDT (Weiss Distribution Technique) with a thin needle to break up clumps and ensure even density.

Tamp: Tamp firmly and evenly with 15-20kg of pressure. The surface should be level and smooth.

Extract: Lock in the portafilter and start immediately. Target 36-40g output (1:2 ratio) in 25-30 seconds. Espresso should flow like warm honey, starting slow, then forming a steady stream with visible striping.

Evaluate: Good espresso has thick crema, balanced sweetness and acidity, full body, and a clean finish. Adjust grind based on taste and timing.

9Barista Method

The 9Barista is a remarkable stovetop espresso maker that achieves true 9-bar pressure through clever thermodynamics. It requires precise grind adjustment but rewards you with genuine espresso at home without electricity.

Dose and Prep: Dose 16g of coffee. The 9Barista is less forgiving of uneven distribution than machines with flow control, so WDT is essential. Break up all clumps thoroughly.

Tamp: Tamp firmly and level using the included tamper. The basket is shallower than standard portafilters, ensure even compression.

Assemble: Fill the lower chamber with water to the fill line. Lock the portafilter into position and screw the upper chamber on firmly.

Heat: Place on medium-high heat. The 9Barista uses a two-chamber system-water in the lower chamber heats and pressurizes, forcing water through coffee at 9 bars into the upper chamber. This takes 4-6 minutes.

Listen: You'll hear brewing begin, a steady hissing as espresso flows. When you hear the sound change to rapid bubbling (like a percolator), remove from heat immediately. This indicates extraction is complete.

Serve: Carefully disassemble (it's hot!) and pour. The 9Barista produces 60-70ml of genuine espresso with crema.

9Barista Grind Notes: Start at 315 microns. The 9Barista is particularly sensitive to grind; 5 micron adjustments make noticeable differences in extraction speed and pressure build-up. If extraction is too slow (taking over 6 minutes to start flowing), move coarser by 8-10 microns. If too fast (flowing within 3 minutes), go finer by 8-10 microns. Once close, 3-5 micron tweaks fine-tune the balance.

Troubleshooting

Channelling (fast, uneven extraction)? Your coffee has dense clumps or uneven distribution. Use WDT thoroughly. If persistent, try 3-5 microns finer to increase resistance and slow flow.

Too bitter, astringent, or harsh? Move coarser by 8-10 microns. Also check temperature; reduce to 92°C if possible. Over-extraction is common when grind is too fine or temperature too high.

Too sour, sharp, or thin? Go finer by 8-10 microns to increase extraction. Also consider raising temperature to 94-95°C. Under-extraction often combines grind and temperature issues.

No crema? Your beans may be stale (over 4 weeks old), or extraction is happening too slowly, degassing the crema. Try 5 microns coarser to speed flow slightly.

Inconsistent shots? Espresso multiplies inconsistency. With grind locked at a specific micron measurement, you can isolate other variables: dose accuracy, tamping pressure, puck preparation, or machine temperature stability. Even 2-3 micron variations can affect shots, so grind consistency is paramount.

9Barista stalling or spurting? Too fine—pressure is building excessively. Move to 325-340 microns. Also ensure your puck isn't over-tamped, which increases resistance.

9Barista brewing too fast? Too coarse. Dial down to 305-315 microns. The 9Barista needs adequate resistance to build proper pressure.

Dialling In Process

Espresso dialling is systematic, not random:

1. Start at 325 microns with your target dose and ratio (18g in, 36g out for machines; 16g in for 9Barista)
2. Pull a shot and time it - Don't adjust anything else yet
3. If 20-35 seconds: Taste it. Adjust by 2-5 microns based on flavour
4. If under 20 seconds: Go finer by 10 microns and pull again
5. If over 35 seconds: Go coarser by 10 microns and pull again
6. Once timing is right (25-30 seconds), make 2-5 micron adjustments based purely on taste
7. Document your final setting for that specific coffee

This systematic approach prevents the common trap of changing multiple variables simultaneously.

Final Tips

Fresh beans are critical. Espresso demands coffee within 7-21 days off roast. Too fresh (under 5 days) and CO2 causes channelling. Too old (over 30 days) and you'll struggle to extract sweetness or produce crema.

Water quality impacts espresso more than any other method. Use water with 75-125 ppm total dissolved solids. Too soft water under-extracts; too hard causes scaling and bitter flavours.

Keep a detailed log. Record: coffee name and roast date, exact micron setting, dose, yield, time, temperature, and tasting notes. Espresso has more variables than any brewing method—documenting them is the only way to achieve consistency and improvement.

Pre-infusion helps, if available. 3-5 seconds at low pressure (2-4 bars) before full extraction saturates the puck evenly and reduces channelling.

Clean your equipment obsessively. Espresso oils build up quickly and turn rancid, ruining flavour. Backflush machines daily with detergent. Clean the 9Barista thoroughly after each use.

Espresso rewards obsessive precision. The ability to make 2-5 micron adjustments isn't overkill' it's genuinely necessary at this brewing method. Under 9 bars of pressure, these minute changes in particle size create measurable differences in flow rate, extraction yield, and flavour balance. Master your grind control alongside puck preparation and temperature management, and you'll consistently pull exceptional espresso that rivals any café.