How I automated my coffeepot and only spent $2,900

The true cost of a cup of coffee

Posted: By Jon Peddie 05.25.22

Back in 2015, I bought a Gaggia Brera espresso machine for our office; it cost  $450, and for that type of machine, it was a steal.

The Gaggia was, and is, great, works like a charm, makes perfect café lattes in three minutes, at the right temperature. It has an instant heater, a bean grinder, and a steamer/hot water dispenser—everything you could want. One of the best-engineered machines I’ve seen.

Before I got the machine, I would go, or ask someone to go, to Starbucks and get a 12-oz. café latte—I’d do that two or three times a day. That came to $12 with tip for three cups, plus transportation costs. At $5 per gallon of gas (California prices at the time), a 25-mpg car (sporty, not an econ) and a 10-mile round trip, that added $2 per cup, plus the cost of labor to drive to Starbucks (20 minutes round trip), which added another $13.33 per cup, for a total of $19.33 for a single cup. So, $58 per day for three coffees, just for me—and I did that five or six times a week. 

A café latte uses about 21 g (0.74 oz) of coffee. Forty ounces of Italian roast is about $27, or about 54 cups of coffee, or 50 cents per cup. Factoring in the cost of water, electricity, and milk, the Gaggia Brera could make café latte for about 72 cents, plus labor (it takes about 5 minutes start to finish, including cleaning, to make a café latte, at $40/hr; that’s $3.33 per cup), for a total cost of $4.04 per cup, or $12.12 a day.

So, if Starbucks was costing $58 a day for me, and three cups made with the Gaggia was $12.12 (see box), then I would save $45.88 a day, which meant the machine, fully costed, would be paid off in 10 days! Amortization of the machine is estimated at 10 years (we’ve been using it for six years and it shows no sign of age). With a 10-day payoff, I could buy a new machine every year and still come out ahead.

But there was another cost factor. Although the machine was almost totally automatic, it has a water reservoir—a little tank that slides out the front for refilling (just under the steamer in the photo above).

The machine has all kinds of alarm symbols to tell you when you’re low on beans or water. But it uses a lot more water than beans because in addition to making a great cup of coffee, it also has a milk steamer, and it gives itself an internal bath when starting up and shutting down, and before and after every cup of coffee—there is nothing about this machine not to like—it keeps itself clean and purrs like a cat.

The water reservoir holds 40 oz. An average cup of coffee is 6 oz. Steaming and cleaning take another 4 oz., meaning you can get about 10 cups of coffee per reservoir filling. In practice, you’re lucky if you get eight. And it takes about 25 seconds to fill the reservoir, which costs 28 cents a day in labor—that’s just outrageous.

I got tired of filling that little reservoir and decided to put in a float valve and hook up a water feed. Seemed like a straightforward solution.

Step 1 was finding a float valve that would fit in the tiny tank—it is only 2.5 inches wide and 5 inches deep. It took a while to find some online—this isn’t stuff I normally buy. They are made for aquariums and reverse osmosis systems. It took me three tries to get the right-sized float valve—evidently, I can’t read specifications as well as I thought I could. The valves cost from $12 to $18, so I spent $21 on float valves with one sitting in a box and one I had sent back.

To get the valve to fit in that little tank, I had to remove the water filter. I decided to replace it with an external and much larger filter. That cost: $18.70 plus $14.95 for the housing. How many days would I have to fill the tank to pay all this stuff off?

Next, I had to tap into the water feed and drill a hole in the counter to run the tubing. The coffee machine was in the office kitchenette, so it was easy to get to and unscrew the line to the faucet and put in a T-fitting for the water feed. In fact, I did it three times until I finally wrapped enough Teflon tape around the threads so it wouldn’t leak. That left an annoying, and embarrassing, amount of water on the bottom of the cabinet. The cabinets were made from laminated pressed wood, and they don’t much care for water, as I would find out.

I ran a quarter-inch clear plastic line from the tapped water feed to the coffee machine and installed an in-line manual valve so I wouldn’t have to crawl under the sink if I needed to turn off the water. That was one of my smarter moves, although I still had more visits under the sink coming than I wanted.

To fit the valve in the tank, I drilled a hole in the side, up near the top and front of the tank. As might be expected, the acrylic plastic was more brittle than I anticipated, so naturally, it cracked. I patched it, but that changed the wall thickness, and the tank wouldn’t slide in nicely nor smoothly. I was getting tired; my 1–2-hour-max project had already hit 5 hours, and I had other things I needed to do. I decided I would buy a new tank and use it while I jury-rigged, er engineered, the float arrangement. I also had to cut a hole in the side panel of the machine to accommodate the water feed to the tank. There went whatever warranty I might have had.

A few days later, with fresh enthusiasm and ideas, I eagerly opened the box containing the new $50.12 water tank. A voice in the back of my head queried, how much does it cost to fill that tank manually?

Now the hard part started—fitting and mounting the float valve. The one I finally got to fit was too long, but I was able to squeeze it in by angling it downward; the tank never completely filled, but the water supply could keep up with the machine’s water usage.

The float valve angled downward in the tank.


The next step was to get the in-line water filter installed. The first try was easy, and except for water squirting out of both ends, it looked pretty good. The kitchen countertop was cleaner than it had ever been, thanks to all the mopping up I was doing. So far so good… until I opened a drawer to get more towels. All the cabinets, and everything in them, were soaked.

I finally got the fittings taped and tightened well enough that the water stayed in the filter and the quarter-inch poly tubing. A little tweaking on the physical orientation of the float valve, and presto, I had an automatic refill system. It was 2016, and I buttoned everything up and patted myself on the back for creating a cool coffee machine and a fun two-hour project that took four and a half days and cost a couple of hundred dollars in parts. I’d calculate later how many cups of coffee I’d have to drink to amortize that.

By 2019, the in-line filter had lost all its color and was way past its use-by date, so I ordered a new one, $19. But when it arrived, it was a different size than the one I had. The good news was this filter came in its own case and with press-to-fit pipe fittings in each end—what could be simpler?

Just stick the tubing in the end, pull, and lock in place.


Up to the beginning of 2021, the system ran well. When I came into the office one morning, the kitchenette floor was covered in water, and I banged my head on the drainpipe, hurling myself under the sink to turn off the water to the coffee machine. The water got as high as the top of the doorjamb to the garage. When I looked in the garage, the floor was covered in water, and it was going into the French drain in the driveway. It must have been running all night, but why? I immediately suspected my float valve, and after getting everything mopped up and inspecting it, it looked fine. Nothing looked broken, twisted, or out of place. I gritted my teeth, put some new dry towels on the counter and floor, and climbed back under the sink to turn on the water so I could find the leak. The problem is, when I was under the sink, I couldn’t see what was happening up on the counter, so water would be coming out when I stood up. And was it! Right out of the top of the new filter. The top had actually blown off.

Fortunately, because of my uncertainty about what to get when ordering the filter, I accidently ordered two, so I had a spare. Installing it was just as easy as it was the first time, but each time a filter is installed, you have to cut the tubing to the old one, which means the poly tubing will get shorter each time. I could see tube splicing was in my future.

I checked everything and tuned on the water, ever so slightly, to see if there were any leaks. Gradually, I raised the pressure, held my breath, and watched. OK! No leaks. On with the day.

The next morning was like Groundhog Day all over again—water everywhere… on the floor, the counter, in all the drawers; God, what is our water bill going to be?

This time, the top of the filter didn’t blow off, it screwed off—just a bit, but enough to let water out. After I finished mopping things up from the now cleanest floor and garage ever, I disassembled the filter, taped the hell out of the threads, and torqued it back on—it might explode again, but it sure as hell wasn’t going to work its way off.

I needed a fail-safe backup. I also needed new hobby.

Back to Amazon, where I ordered an E-SDS automatic water leak detector sensor with shutoff valve and alarm—$108.24. The first problem was that the ball valve had three-quarter-inch fittings, which meant back to Amazon for three-quarter to one-quarter adapters. Seems the shutoff valve was designed for water heaters and not aquariums and abused coffee machines.

The installation was easy, and I used double-sided tape to mount the sensor on the body of the valve with the sensor pins touching the counter. Then I turned on the water, scringing as I did, expecting a fire hose leak somewhere in the long chain of parts I had now put in the piping to the coffee machine. Nothing. I got it right on the first try; every once in a while you get lucky.

The long route to the float valve.


Now came the important test. I poured some water on the counter near the sensor and watched it spread. When it got to the sensor, there was a resounding and very satisfyingly loud CLUNK—the valve had shut. I pulled out the water tank and pushed the float valve down, and no water came out—YAY! It works. The shutoff valve was the first item in my parade of tubing accessories. Not only did it work, but it set off a horrendously annoying high-pitched alarm—anyone within 100 feet would know something was wrong. Slightly more expensive models have Wi-Fi so you can be notified on your phone. What you’d do with such information was a mystery to me.

The control panel of the auto-shutoff valve—you don’t want to be near it when it goes off.


The system was now as bulletproof as I could make it.

But the cabinets were ruined. None of the drawers would open without herculean effort, and the bottom shelf that the mini-refrigerator sat on looked like rats had been chewing on it.

Water-damaged cabinet—notice how clean the floor and countertop are, though.


This was during the lockdown, and finding someone to repair the cabinets was challenging. Finally, through Handyman Heroes, I found Michael. He was great, and I learned after he was finished that he was from Philadelphia, where I came from—all the cool guys are from Philly. He did a great job rebuilding the cabinets, but I was a bit shocked when the $2,100 bill came. Yikes! Now, how much coffee would I have to drink?

The cost of going to Starbucks two times a day, four days a week, for 48 weeks would be over $7,400 a year, so my $2,900 never-run-out-of-water coffee machine will pay itself off in a little over three months, longer if the cost of gas and/or labor comes down; don’t hold your breath. But I do miss those rides to Starbucks, especially on a spring day with the top down, radio playing, sipping a coffee. Truth be told, I still go. On my last ride, I was thinking about how to increase the coffee bean bin capacity so I wouldn’t have to refill it so often….