1.015 gravity in starter

[Dale Gauthier]

Hi all,
First starter from harvested yeast, pulled a reading from the starter (pulled from thin wort/beer ontop the slurry or yeast cake).

Anyway, it reads 1.015 on the refractometer. I know it should be more like 1.030 so I'm low. Do you think I'll have a problem getting the beer fermentation to take off? I'm brewing (BIAB) AHS Gold Seal British Ale from Austin Brew Supply.

Instructions say the OG should be approx 1.050 with a final of approx 1.012.

Think I'm ok to pitch this starter or should I scramble to get a smack pack and scrap the starter? I'd hate to ruin 5 gallons of wort!
Thanks all

 

[deadwolfbones]

if you're taking a refractometer reading post-fermentation in the starter, it's going to be skewed by the presence of alcohol.

but anyway, it definitely shouldn't be 1.030 after the yeast has had time to reproduce (aka eat the sugars in the starter).

 

[Dale Gauthier]

if you're taking a refractometer reading post-fermentation in the starter, it's going to be skewed by the presence of alcohol.

but anyway, it definitely shouldn't be 1.030 after the yeast has had time to reproduce (aka eat the sugars in the starter).

Ah I see. The reading should be taken with the refractometer before starter ferm. I did that and it read about 1.025.
So I guess it dropped that much in the past 24hrs. Guess I’m ok ...

 

[Gnomebrewer]

It's actually dropped more than that. As deadwolfbones said, refractometers don't work after fermentation starts (unless you use a correction calculation) as the alcohol skews the sugar reading. A reading of 1.015 after fermentation starts means the true gravity is several points lower.

 

[Dale Gauthier]

Oh wow. Ok, so I can use the refracto before ferm and I guess I should use my old hydrometer for during and post fermentation?

 

[cactusgarrett]

You can still use a refractometer post-ferment (it's definitely useful with small volumes), you just need a pre-ferment reading and a conversion tool.
http://seanterrill.com/2012/01/06/refractometer-calculator/

 

[deadwolfbones]

You can still use a refractometer post-ferment (it's definitely useful with small volumes), you just need a pre-ferment reading and a conversion tool.
http://seanterrill.com/2012/01/06/refractometer-calculator/

That one is good, but this one is maybe a bit easier to use: https://www.brewersfriend.com/refractometer-calculator/

 

[deadwolfbones]

Anyway, good news is you have a viable starter. Use it!

 

[Dale Gauthier]

Thank you both! Did some more reading and I clearly see that the refracto is not the quick and easy I thought it was. I’ll work on the correction factor and all but my big take-away was post ferm refracto readings need attention.

Thx!