That is the question. Assuming one has a machine that allows for either option, which is simpler and preferable? Pros and cons?

In addition: Does the pre-infusion on an e61 - on a machine that is not plumbed in - suffer as a result?

If you can plumb thee is little reason not to. It frees you from the ever-repeating task of filling the reservoir, or even thinking about it. If you can also plumb the drip tray, even if just into a large under-cabinet bottle, you will never want to go back to dealing with walking a full drip tray to the sink.

In terms of preinfusion, and assuming the machine is rotary-pump equipped, plumbing offers a user control over that not available in a reservoir machine. I had been getting a bit of an over-extraction with my method of waiting for a drop to fall into the cup, so I preinfused just ten seconds this AM and it made a big difference for the better.

I am under the impression that the pre-infusion lacks pressure if the machine is not plumbed in. True? How exactly does e61 preinfusion work on a reservoir DB machine anyway? Doesn't the pump take care of it? Why does being plumbed in change anything?

My hesitation with plumbing in would be 1. Water hardness and the whole de-scaling issue, 2. Chlorinated water changing the taste (currently using RO filtered water).

Plumbing in usually involves running the water through a filter and softener system, so chlorine and scale are less of an issue. Also, if you get a machine that can run off a tank or be plumbed in, then you can use the tank to descale and plumb in for day to day use.

An e-61 machine, whether plumbed or tank fed, has built in preinfusion through a special chamber in the group. However, if the machine is plumbed in, you can also preinfuse with the middle position of the brew lever, which opens the valves without turning on the pump. This allows you to preinfuse at a lower pressure than with the built in preinfusion chamber.

As was noted, the manual preinfusion is only available when the machine is plumbed, while the inherent and non-adjustable E61 preinfusion is always in effect, working much like the optional preinfusion kit for the Vivaldi Mini. In a plumbed setup, you control the preinfusion's duration (via brew lever) and rate (via supply pressure regulator). In modern E61 machines, electronic boiler water level sensors require some mineral content to function, so a pure RO water source would need some re-mineralization, either back-blending or addition of a calcite cartridge to the filter system. Bear in mind too the corrosivity and reported poor taste of highly purified waters (RO, distilled), though I thankfully have no personal experience to relate.

I can't imagine having a pour-over machine ever again. I had to fill the reservoir in my La Valentina every day or two, which was a royal PITA. The only thing I wish my machine had now was a plumbed drain/drip pan.

genovese wrote:In modern E61 machines, electronic boiler water level sensors require some mineral content to function, so a pure RO water source would need some re-mineralization, either back-blending or addition of a calcite cartridge to the filter system. Bear in mind too the corrosivity and reported poor taste of highly purified waters (RO, distilled), though I thankfully have no personal experience to relate.

1. How does the water level sensor work? I thought it was a simply buoyancy marker. How would minerals in the water affect it?

2. Althought the taste of RO filtered water is not wonderful, it is much better tasting than the chlorinated water that comes out of my tap.

The water sensor is an electric probe inserted into the boiler. It's positioned in the boiler such that, once the boiler water reaches the optimum level, the water touches the probe, which creates a circuit and shuts off the pump and closes the solenoid to the boiler. If the water is completely free of minerals it won't conduct electricity properly, and the circuit won't be created and the boiler will keep refilling until it overfills. So it's important to have some minerals in your water, although not so much that it creates scale problems.

For a much longer and better explanation of how much mineral content your water should have, read the insanely long water FAQ written by Jim.

The filtration system should remove the obnoxious chlorine taste and smell from the water, which is a separate issue from the mineral content.

innermusic wrote:2. Althought the taste of RO filtered water is not wonderful, it is much better tasting than the chlorinated water that comes out of my tap.

The taste of RO-water-brewed coffee is very inferior to coffee brewed using water with some minerals (50ppm+).

I plumbed in for about 4 years. Recently I moved to a place that didn't offer a convenient plumbing solution, so I bought a flojet system. Actually, I built one myself using a high-flow delivery pump and a large (2 gallon) accumulator that means that the system only re-charges once a day or less—and takes about 8 seconds to do so—but the principle is all the same: you draw from a 5 gallon bottle under the counter. In this configuration, a bottle lasts me about a week or so. I also installed a carbon filter in the delivery pump setup as well, which allows me to hold chlorinated water in the tank. I feel like this is probably a bit safer in terms of the risk of algae buildup, etc. in the bottle, feed tube, and water lines.

Using such a system is a bit of a headache compared to plumbed-in: once a week I replace the tank, formulate my water, and dump the waste bucket. But it does give me the advantage of being able to mix my water to desired TDS levels (I shoot for 100-120 ppm TDS). I mix tap water (unfliltered) with RO water. It gets carbon-filtered prior to entering the machine as I said. Before, I was using Everpure Claris. That system is great, but it was certainly related to some annoying issues with non-scale, verdigris type buildup in my boiler which has reduced dramatically since I switched to a lower-TDS system.

YMMV, of course, but that's what I've been doing the last 5 months. I'm pretty happy with it. As an added bonus, if there's a leak or other disaster, the worst that can happen is spilling a few gallons of water on the tile floor. It'd be a mess, but better than a totally flooded house.

I think the advantages are largely dependent upon the particular machine. With many, it's a simple trade-off between the convenience of not filling the reservoir versus any plumbing expense and filtration compromises (if any, e.g. you prefer the flavor when using a Brita etc.)

With other machines the compromises will vary. My experience with the GS/3, for example, is that without plumbing, its pre-infusion is more like "pre-delusion" and the resulting un-plumbed pre-dribble is uneven and hurts the shots more than helps them. However, LM experts seem to be fairly noncommittal on the value of even a plumbed PI with the GS/3 anyway so the loss may not be significant.

Meanwhile, plumbing would be more convenient, although the reservoir's easy front access is well designed and minimizes frustration - at least, until you forget to reload for a couple days and you get the "REFILL ME" message just when you wanted to pull a shot. On the opposite side, the machine (oddly, in my experience) runs quieter if you run it with the drip tray 1/2 - 2/3 full: it seems to dampen vibration. So if you plumb the drip tray drain, you lose that and the easier cleaning of the tray when untethered.

Still, if we didn't have non-drillable granite counters (orders from HQ) and the filtration were easy and not too expensive, I would certainly try it.