Temperature surfing a Gaggia Baby

[markbatey]

I've been attempting over the past couple of weeks to temperature surf my Gaggia Baby to try to get some sort of consistent water temperature out of it. I had read somewhere that waiting 10" after the heater light goes on (indicating that the heater has switched off because the machine is up to temperature ) gave the best temperature to work at.

This morning I thought I would test this out. I ran some simple tests using a plastic cup, a milk thermometer and a timer. With the portafilter removed I drew off around 70ml of water to drop the internal temperature and switch on the heater element. I waited until the heater light went on. Then I waited different lengths of time and measured the temperature of a double shot in the plastic cup.

I know this won't give accurate absolute temperature of the water as it hits the grinds in the portafilter. I was more interested in the variation in temperature over time, and I think this method should give an indication of that.

Here's the results:
Time Temperature
0 68
30 67
1.00 73
1.30 73
2.00 71
2.30 71
0 65
30 67
1.00 70
1.30 71
2.00 70

Calibrating my milk thermometer in boiling water it's reading about 5C too low. Plus there's a big temperature drop as the water falls into the cup, so these are not accurate absolute readings.

But what seems to be consistent is the lag between the heater element switching off and the water reaching its maximum temperature. It takes at least a minute to get there, then the temperature drops fairly slowly over the next minute or so.

I'm going to try working in that range of one to one and a half minutes and see if I see any improvement.

Of course, you guys with the big machines worry about half degree temperature drifts - we can only dream of that stability. But hey, it's all about getting the best out of what you have.

M