I am trying to determine the practical difference between an E61 with dual boilers and PID and a saturated brew group. The articles I have found seem to predate the recent rise of DB E61s. Additionally, does an E61 with DBs require the same pre-shot flush?

E61 groups have been used on single boiler, no HX, home machines by VBM and Isomac since the late 1990s; so the issues of using them in this way had been pretty much solved by the time they were used on DB machines. At that time, temperature stability of around 2 to 3F was considered fine; while nowadays, the engineering types are expecting tighter tolerances. Both E61 and saturated groups have been tweaked to achieve this.

However, actual performance depends on proper tuning of each model, not the technology used; the champion as far as temp stability goes is still the Nuova Simonelli Aurelia, an HX machine. In general, models that have a tuning problem get withdrawn and come as a version two a year later. You'll get the skinny on the models we review here.

Practically, assuming proper tuning with a good PID, I'm not discerning much difference in an E61 on a DB and a saturated group. Yes? No? And I am fully aware that "practical" is a non-existent factor at this level.

The taste difference within the two groups of different iterations of the E61 or of saturated groups will be just as high as the difference between the groups.

Can someone please give me an example of a saturated brew group? Is it just any one that isn't an e61?

Saturated group examples:
1. LM GS/3
2. KvdW Speedster
3. Synesso Cyncra
4. Slayer