STREGA: THE MOVIE
(Hint: the videos play best in full screen; total length is about 25 minutes)INTRODUCTORY
: Bezzera has designed the Strega to be as simple to use and convenient as any semi-commercial pump machine. This includes the innovative use of an HX and group head heater to stabilize the lever temperature, and standard Ulka pump to refill the boiler and prime the lever from a standard pourover tank.WHO SHOULD BUY IT
: Despite the design tweaks to make it a semi-commercial machine, the Strega lever still requires muscular effort, it is not counter friendly, and it is slower for continuous shots than a pump machine. However the combination of a lever and nine bar pump gives a wide range of pressure profiling capabilities. This permits making brilliant espresso from coffees, including the Esmeralda Geisha, that cannot be used on pump machines.PRESSURE PROFILING ON THE STREGA:
The attraction of a lever machine is that it can be played like an instrument. The Strega's combination of lever and pump multiply these possibilities. On the Strega, the pressure of the preinfusion, the early, middle and late part of the shot can be separately controlled. This allows the Strega to emulate the operation and taste of a wide variety of high end espresso machines.
I would like to highlight that this lever/pump combo requires either an unusually fine grind or a high dose. It is better to keep the grind in the normal espresso range and add about 2 to 3 grams to the dose of normal double baskets. This will get the shots I describe in the videos. Using very fine grinds will usually get overly flat and sweet comfort food shots.UPDATE:
(Abbreviated Shot Making Instructions)
The following is a short step by step instruction for making shots that was initially a part of the draft front page review
. Due to the shortened format, and since this information is available scattered throughout the thread, it was cut. Here it is, for reference:
If you want the master class shot with the flavor clarity of classic levers, but the denser body and crema of pump machines; here is the drill:
- No flush is required if you want to minimize acidity. If you want to bring out the acidity, the longest flush needed is about four to five seconds, until the flash boiling stops. Longer flushes than that are unnecessary, since the group itself does most of the temperature regulation.
- Allow the pump to run until it fills the group, quiets down (indicating 9 bar pressure) and until you see a slow flow of espresso. This takes about ten seconds; E61 users will feel right at home with this part.
- Now lift the lever slightly, enough to shut off the pump, but not enough to engage the spring. Let the compressed air continue to force out the espresso in a slow flow. This trick adds both to the body and clarity of the shot, but I cannot explain why.
- Once the air is decompressed and the flow slows down, lift the lever and engage the spring. But keep your hand on the handle and control its rate of rise, in order to maintain a steady flow. Keeping the flow very slow and steady will produce a dense, viscous shot without much crema; while a steady normal flow rate will produce a shot with pump espresso body and crema. The best tasting alternative here will depend on the coffee and your mood.
- To end the shot, once the coffee stream blonds or the volume is sufficient, pull the lever down slightly, so the flow stops; and remove the cup.
I've tried many other variations, including running the pump for longer into the shot, or cutting the pump early in the preinfusion, then waiting, then turning it back on (to copy the line pressure preinfusion of pump machines). These experiments produced only mediocre shots for me. As far as I can tell, the machine is at its best and most characteristic when the pump is used for preinfusion portion of the shot, and the lever is used for its flow portion.
A note on draining and filling the boiler by siphoning when descaling. The holes for the the vacuum breaker and pressure gauge fitting are too narrow for most hoses. The safety valve requires a large amount of torque. So the best fitting to use is the steam valve's, which requires only gentle torque to open and close, and has a large enough hole to accommodate the standard espresso machine hoses.
The boiler fill control allows a fill of approximately 0.75 liters; the entire boiler is full to the upper fittings at 1.375 liters.
As far as I can tell, there are no nooks or crevices that preferentially scale; so descaling intervals can be fairly long. You may want to rinse-descale just the HX more frequently, and the boiler less frequently, unless you do a lot of steaming or use the hot water tap regularly.