Glossary of terms

by Bruce Colglazier Pappas

ACTIVE PREINFUSION

• Asserting lever pressure to saturate the puck before, during, or upon actual extraction. Lots of variations and timing therein. Used to extract specific flavor notes & better body. Care is needed to avoid overheating/overextraction for the steam heated GH (Gen 2)

BONG'S ISOLATOR

• A modification developed by Bong Juachon and other LP owners to limit steam entering the grouphead in order to limit overheating. Most useful for Gen2 machines.

CHOKE

• Grind is too fine and has compacted. The water is unable to penetrate puck. If you suspect you have ground too fine, you can sometimes save the shot by tamping very lightly.

COLD PRIMING

• After filling, before turning on, pump lever until cold water flows through shower screen. For water heated group heads only (Gen1 & Gen3), removes air pockets from pipes/sleeves/GH, primes machine. Concept develped by Osku Tervonen.

DIALING IN YOUR SHOT

• Grind, dose, tamp, pre-infusion, extraction pressure/time used for a particular bean. All beans require being dialed in, and will require tweaking as they age. Different bean origins and roast levels will be dialed in differently.

DRY PUMPS

• Before you engage PF (portafilter), raise and lower lever to the point just before water flows from shower screen. Repeat 5-10x, or until the GH reaches your desired temperature.

FALSE PRESSURE

• After you bring your LP to boil when the release valve whistles, open the steam wand to release the air from boiler. Also flush water through the GH to remove air from the group head. All machines require this. Also helps to warm the GH.

FALSE TEMPERATURE

• A slow thorough warm up to desired temperature will perform differently/better (more stable) than the same temperature raised from cold to hot quickly (unstable).

FELLINI/MINI-FELLINI

• Mini-Fellini: lift lever, squeeze down to first drop, lift again, preinfuse, pull shot as per your normal.

• Fellini: lift lever, preinfuse, ½ pull down 5sec, lift again, pull shot. These are used in different ways/times particularly for active pre-infusion. Also used to increase volume output. Note: Gen 2 may over-extract using Fellini.

Gen# (example: Gen1) or v#.# (example v3.1)

• Design changes in LPs over time. For details, refer to Francesco Ceccarelli's website. Commonly referred to as:
  Gen1 = vintage
  Gen2 = Pre-Millennium
  Gen3 = Millennium
  Gen4 = Stadivari
  Specifying the generation and the model helps with machine idiosyncrasies and finding the right replacement parts.

GH

• Grouphead

LP

• La Pavoni. Also LP Ep or LP Pro for Europiccola or Professional.

NUTATION

• Tamp edges of puck primarily. Nutation can promote even extraction, help eliminate donuting, and squirting issues. Reference1 and Reference2

PID

• Proportional–Integral–Derivative controller. A device that is designed to achieve a constant value of a variable in a system. In our context, that’s usually the pressure inside the boiler (which is related to the water temperature through steam physics), by means of turning on/off the heating element carefully. The terms in the acronym refer to the way that the device achieves its function: it combines corrections (i.e. turning the heating element on/off) that are (1) proportional to error, i.e. the difference between the current and desired value; (2) proportional to the integral of the error, i.e. the accumulated value of error over time, once this accumulated value stops growing, that means error is truly zero, this allows to get rid of residual errors; and (3) proportional to the derivative of the error, i.e. the rate of change of the error, this prevents over/undershooting in the applied corrections. Simpler versions of a PID controller are P, PD, PI, etc. controllers, that rely on not all of the above-mentioned strategies to achieve stability. While PID controllers are largely electronic nowadays, they are not limited to that. E.g. a fly-ball governor and toilet tank valves are P controllers; different types of thermostats and pressurestats can be of these types too. For the La Pavoni lever machines, a PID pressure controller allows quick, precise and reliable setting of the boiler pressure (and thus water temperature) for brewing and later raising of it for optimal steaming of milk, if desired. It doesn’t, however exert any control over the grouphead temperature. This needs to be dealt with by the user (e.g. with grouphead flushes or dry pumps) or other dedicated control systems. [Source unknown]

PF

• Portafilter

PSD

• Particle Size Distribution

RDT

• Ross Droplet Technique. Dip the handle of a small spoon into water and stir the beans with it. This puts a small amount of water in the beans and reduces grinder static. Reference and YouTube

SIFTING

• Sift grinds into layers. Reference

SNEEZE

• After pulling a shot, when the PF is removed to quickly before the pressure has adequately released from the GH and water & coffee grounds spray everywhere. A good sneeze is a prerequisite to graduate as a La Pavonista! Simply - you need to wait! You can assist the pressure drop by releasing the steam wand & by half lifting lever to force pressure away from GH back into boiler. You can also jiggle the PF slowly before it is released from the GH.

TDS

• Total Dissolved Solids

WDT

• Weiss Distribution Technique. “The WDT involves stirring the grounds with a thin object (such as a dissecting needle), known as a Distribution Tool (DT) to break up clumps and even the distribution. Stirring creates a uniform distribution of grounds throughout the filter basket, which is impossible to achieve by pushing the grounds around the surface of the puck. You need to get all the way down to the bottom of the basket, and the needle permits this.” Reference1 and Reference2

Created 07-DEC-2018 | updated 31-JAN-2023 | BCP