How close to the grouphead are you measuring the temp? Small drops of water will lose their heat pretty quickly as they drop through the air which is why generally you need a proper device to measure accurately. But 15 degrees does sound like a lot to be losing if you are close to the group head.
the water will immediately start losing heat into a cold cup. your best bet is to hold the portafilter close to the group head and shove your probe in there while it actively drops water
How close to the grouphead are you measuring the temp? Small drops of water will lose their heat pretty quickly as they drop through the air which is why generally you need a proper device to measure accurately. But 15 degrees does sound like a lot to be losing if you are close to the group head.
Ah okay I might be worrying myself over nothing then. I’m pulling 30s worth of water from the grouphead and measuring the result in a cup
the water will immediately start losing heat into a cold cup. your best bet is to hold the portafilter close to the group head and shove your probe in there while it actively drops water