thin krausen

You pitched a ton of yeast for that size of batch, it's possible fermentation already happened. What's the trub layer look like? Do you have a refractometer for gravity readings? I'd hate to suggest a hydrometer reading given the 1 gallon batch size.

 

I was thinking 10-11g was standard for one dry packet which is suitable for 5 gal of low-moderate gravity beer when rehydrated.

Two questions:

Is the layer of trub larger now than it was half an hour after pitching the yeast?

Do you have a refractometer?

 

I see this every time I use 3724 (Dupont dregs). I'll put 5 gallons in a 6.5g primary and the high-krausen mark may be all of 1.5" . . . yet the yeast does it's job, I get super attenuation. So I say it's normal. Your other two batches . . . different yeasts?

With 3724 I believe you're talking liquid yeast and your reference to 25g may be a little confusing. With liquids it's usually referred to as 25ml (which of course is 25g). By pitching 1/5 of a liquid yeast packet into 1 gallon of wort you are in the ballpark if the yeast was fresh. You have the date of the packet?

 

Good catch, I saw 25g and assumed a dry yeast

 

Refractometers don't work once fermentation has begun, as they can't accurately read alcohol. Unfortunately a hydrometer is the only way to go at this point. If the OP is confident in his/her sanitary practices, they could put the sample back in the fermenter.

 

I'd let it roll and not worry too much about the krausen level. Take a gravity reading in a week, and if nothing really happened, I'd re-pitch. It's possible that your yeast wasn't totally viable.

 

they work fine if you know the OG

 

Please explain, cause this would be great to know! I tried once, and there was no line. The whole thing was blurry.

 

It's possible there was an air bubble or the cover wasn't completely seated. There should be a line with an adequate light source. There are online calculators to correct for the alcohol content, one being:

http://www.brewersfriend.com/refractometer-calculator/

 

This is fantastic! Thanks! I'll have to try it out. I wonder how accurate it is.

 

The best standalone refractometer calculator I've used is Sean Terrill's. Here's an on-line version...http://seanterrill.com/2012/01/06/refractometer-calculator/
There's lots of good information about refractometers and the corrections needed to make them useful for beer on his site.
Sean's model is excellent, but in order for it to be as accurate as possible, you have to get the Wort Correction Factor (WCF) right.

Sean's model is also incorporated into BrewCipher, with a slight modification - an automatically calculated recommended WCF, based on the expected attenuability from the recipe. This recommendation can be overridden, using Sean's recommended default WCF or any WCF you like.

 

For the blurry line problem, put your sample through a paper coffee filter before measuring. My lines are very sharp after I do that.