Strange hydrometer reading

[bigspoon]

Hi

I'm brewing a Young's bitter kit. Sat night was 8 days from brewing. I used the hydrometer and the reading was 1.006. I tried it tonight (Sun) and the reading was 1.008. Is it normal for an OG reading to fluctuate like this?

 

[Wasabi]

If its cooler today that might explain it, since density is temperature dependent. I'm not sure how much variation you should see per degree C though.

Edit: Just checking my chemistry tables, if I've read them right then with water I think you'd expect a 1 point change per 4°C which suggests it would need the beer to cool by 8°C to get such a rise in density which seems unlikely. Alcohol density is much temperature dependent but I presume your brew is not mainly alcohol!

 

[bigspoon]

It is cooler today. I'll give it another few days. I'm going to put it in a keg.

 

[PD]

Small differences in the readings like this can be put down to how you read the hydrometer. your eye line in relation to the trial jar, the amount of surface foam the level of residual gas in the beer,temperature etc. Unless you want to be absolute about it, its near enough for us humble homebrewers. Split the difference and call it 1007.
Nearly time to bottle or keg...

 

[jonnymorris]

Bubbles on the hydrometer can also give you a duff reading. As PD says, I wouldn't worry about being too precise.

 

[bigspoon]

the reading tonight was 1.008. Is it normal to take this long?

 

[Rolfster]

Did you spin the hydrometer to get rid of bubbles?

As MJ said these can throw your reading off.

 

[bigspoon]

Yes, gave it a good spin.