Tassimo - Fancy a Cuppa?

Friday 2nd May, 2008
Almost exactly three years ago, on my old blog, I wrote about a new drinks maker called Tassimo.

Three years later and the device is far from new but still well marketed. It's still one of the more popular 'pod' style drinks makers and I'm actually on my second device as the previous one died a horrible death sometime earlier this year. It still worked, but wouldn't stop boiling the water randomly. We declared it unsafe, threw it in the trash, took a good look at other alternatives and ended up buying the same again.


Interestingly, before I bought the first unit, I read a few reviews that said the Tassimo made good drinks but many reviewers, including myself, commented that the Hot Chocolate had an unusual chemical after taste. Over the period of ownership I'd forgotten about this and assumed I'd got used to it. When we purchased the replacement unit, sadly the original was out of warranty, I noticed a return of the after-taste. I can only assume this is a "new" taste which goes away with time as the solvents used to clean the device in the factory are rinsed away.

Pod style hot drinks makers have some real added convenience. As you only boil enough water for one cup, making a drink is quick and easy. The system heats a pre-defined amount of water in it's boiler and then pumps it at pressure through the Tassimo T-Disc which brews and dispenses coffee, tea, hot chocolate or even frothy milk.

Of course, from the perspective of the eco conscious, heating just enough hot water is a lot more energy efficient...or is it? What is the power consumption of the Tassimo coffee maker? This is why you read Jaffa's Green Blog.

Using the in-line meter that we used in previous test, we were able to measure the amount of power it takes to make a standard cup of coffee. For the purposes of testing, and retesting, I actually used the cleaning disc that was supplied with the unit. This probably heats the water a little hotter than some of the drinks but also removes most of the variables from the test, such as the amount of coffee in the disc might affect the results. Using the empty test disc should allow consistent, repeatable results.

I turned the unit on at the wall and it entered standby mode at a current draw of 0.01 Amps, some 3 Watts on our UK supply voltage. I inserted the disc and the unit registered the closure of the lid and started heating the water at a rate of 1600 Watts. Incidentally the water came from the on-board reservoir where it had been overnight, safe to say it was room temperature.

The water heated at 1600 Watts until the target temperature was reached and the green READY light illuminated. It dropped back to standby consumption of 3 Watts and the total energy used was 0.02 kWh which wasn't increased when the button was pressed and the 14 Watt pump dispensed the drink.

After dispensing a drink, the instructions tell you to remove the disc. In fact, if you don't, it can get a bit sticky with the concentrated hot chocolate disc left in there for a while - so this is good practice. Interestingly though, the machine has a mind of it's own and so, when you remove the disc, it assumes you're going to make another drink. To save time, it starts pre-heating the water. Energy use shoots back up to 1600 Watts for around 15seconds and the total consumption rises to 0.03 kWh, an extra 50% consumption, for a drink you're not going to make!

To confirm this, I reinserted the T-disc and the READY light instantly lit showing that the unit had pre-heated enough water for the next cup. It didn't use as much energy as last time as there was still water left over from the last run...the unit always heats a bit extra to allow the cups to be topped up if you're drinking from a larger beaker and would rather have a bigger drink.

In case you're wondering, after dispensing the second drink, I removed the disc - again the boiler kicked in to heat more water. Each time you use the unit, you're wasting 0.01kWh of energy for that extra cup you will never make. When you're only making one cup, that a 50% waste. but obviously the proportion of inefficiency decreases as you make more drinks in one session. Of course, if you were making a lot of drinks, you would probably just put the kettle on!

Talking of which, how does a kettle compare? Well, this is what testing is all about....

I removed the Tassimo water reservoir from the unit and tipped the room temperature water into a spare room temperature mug identical to that used in the Tassimo testing. I ensured that the water level of cold water was the same as the amount of hot dispensed by Tassimo. I then poured this water into an empty kettle, a modern kettle with a concealed element in the base.

The first thing I noticed was that the water level was below the minimum allowed on the kettle measure, so I had to top it up to 300ml, Tassimo brewed approximately 250ml. Once topped up, I replaced the lid and connnected up my energy meter.

Standby consumption was zero...when this kettle is off...it's off. I then turned it on to boil, 2200 Watts of energy were used in the process which, with only the bare minimum, was surprisingly quick. I left the unit going until it clicked off automatically, in reality it had been boiling for 10secs or so before this happened, so energy consumption was more than it should have been...as was the case with Tassimo. In fact, Tassimo doesn't even boil the water as it's not required for it's drinks.

End result for the kettle was 0.04 kWh, a little more than the Tassimo for a little more water to be heated a little hotter. So, not much to choose between them really and improvements could be made on both products. The kettle could have cut out a little earlier. Tassimo could, and for eco reasons should, start pre-heating the water only when a new disc in inserted in the machine. Wasting 0.01 kWh of energy each time just in case you want another cup is unacceptable. In fact, if I leave the energy meter connected whilst unattended, I slowly see the energy creep up for no reason. From time to time it just appears to switch on the boiler for a few seconds, you can hear it gurgling and occasionally water will drip down the overflow into the drip tray.

So what's the most efficient way of making your drink? Well a cold drink from the tap would save 0.03 kWh per cup!

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