Stop - thief?

[DanielB]

Hi all, I am confused a little by wine thiefs, hydrometers and refractometers...

I am trying a few brews where one needs to 'check on fermentation' is it correct that a refractometer - whilst maybe the most convenient tester - is absolutely no good once fermentation has started?

To see how a brew is progressing, a thief or hydrometer is the only way to test current SG....?

 

[Horners]

Hi all, I am confused a little by wine thiefs, hydrometers and refractometers...

I am trying a few brews where one needs to 'check on fermentation' is it correct that a refractometer - whilst maybe the most convenient tester - is absolutely no good once fermentation has started?

To see how a brew is progressing, a thief or hydrometer is the only way to test current SG....?

I think that conventional wisdom is a refractometer is useful for brew day before fermentation begins. For example you can take gravity of hot wort as it only takes a drop which cools instantly rather than 80mls or so.

Once fermentation begins the alcohol disturbs the reading. You can calibrate by plotting versus hydrometer readings over a decent number of samples. You may have seen this referred to as wort correction factor. But basically easiest to use the hydrometer once fermentation underway.

 

[kelper]

Monitor the brew with a thermometer and a wine/beer hydrometer. A hydrometer is about three quid. A refractometer will be at least twenty quid. A hydrometer is affected by sugar and alcohol but it's easy to calculate the alcohol by volume (ABV) if you take a reading before and after fermentation. A hydrometer will also tell you when you can transfer from your fermentation bucket to bottles, keg or pressure barrel. A wine Thief is just a gadget to suck up some brew and drop it in the measuring cylinder. Personally, I don't use my wine thief, I just fill the measuring cylinder directly, submerging it in the bucket (after sterilising it) or even putting the hydrometer directly in the 'beer'.

 

[Drunkula]

I often leave a hydrometer in the fermenter so you can have a sneaky peep without letting too much air in**. It'll not read perfectly because it gets krausen stuck to it but it's a really good sign.

Try to get hydrometers with one scale: specific gravity. The Stevenson ones with loads of **** on them just means that SG is NEVER facing you. I do use a syringe to take readings and use the refractometer with a calculator for corrections and it really works for me.

** I've got better at this. I used to take the lid off about every 3 hours and have a taste and wondered why everything I made tasted super-kitty. a) they were beer kits. b) Oxidised to hell every time because of my meddling.