Lower than expected SG, wrong yeast?

[hotbeer]

5 days into my ferment of a beer intended to be 4.1% ABV I did my first SG check for FG and find it is at 1.004 from an OG of almost but not quite 1.044.

I used 8 grams of US-05 and the fermentables are:

98% Rahr 2 row​

2% Breiss Carapils​

​

I hit all my other SG's within a point or 2 while brewing this. My strike temp put my grist at 154°F which is what I held pretty well for 70 minutes.

So assuming it's not infection, which doesn't show yet in the taste, will it be reasonable to think that I should have used a lower attenuating yeast? I was a little skeptical of using the US-05, but it was a previously opened pack from the last batch of a higher ABV version of the same recipe.

Maybe S-33 will have been a better choice. I'll probably wait for it to start to clean up some before the next SG check. Maybe as long as a week.

I did use a hydrometer and the beer was room temp so probably 70 - 71ish degrees.

I'm not really worried about it, but I'm going to do a different recipe before this beer finishes. It is also shooting for an ABV around 4.1%. The recipe calls for Wyeast 1056, but I only care to mess with dry yeast and US-05 I thought is the accepted substitute.

What do y'all think about it getting so low an SG?

 

[Northern_Brewer]

It is also shooting for an ABV around 4.1%. The recipe calls for Wyeast 1056, but I only care to mess with dry yeast and US-05 I thought is the accepted substitute.

What do y'all think about it getting so low an SG?

Yep, US-05 is fine as a sub for 1056.

The first thing I'd do is check the calibration of your hydrometer - if it's .003 out across the board, then that could be 1.047 going to 1.007 for 85% attenuation which is high-normal for US-05. You can get a good idea just by seeing what it reads in plain water, or you can find instructions on the web how to do a multi-point calibration with sugar solutions.

Also, it's always worth normalising hydrometer readings for temperature, even 6°F/3°C away from the calibration temperature can lead to a 1-point under-read.
https://www.brewersfriend.com/hydrometer-temp/
Also typical homebrew hydrometers just aren't that accurate in this kind of range, if you're interested in measuring FGs then it's well worth picking up a "finishing" hydrometer with a range up to 1.020 or so, which is much more accurate for this kind of thing.

 

[hotbeer]

I thought you were going to be correct with your supposition about being off by .003. I just checked it in in 70°F distilled H20 and at first got 1.002ish.

Then I noticed some big bubbles stuck in the grove that goes around the weighted end. After knocking those off, it's 1.000ish.

The ish part is because it's a wide ranging hydrometer going all the way to a useless 1.160. So a jump of .002 is only about 1/16 inch. 32nds of an inch I don't see as well as I use to.

I've thought about the finishing hydrometers before and it's probably time I get one. Also probably need to see about another main hydrometer that doesn't have that groove around the bottom end to trap bubbles and maybe has a narrower range more appropriate for beer.

Thanks for the reply. It gave me things to ponder. And showed that with my current hydrometer, just a few bubbles clinging to it can make a difference.