Low FG

[LarsonLE]

So I brewed a Terrapin Rye Pale Ale clone, my third all-grain batch. It has been fermenting for exactly a week, and I was really excited to see how this batch was doing, so I went to take an FG reading, and I'm getting a reading of 1.004. This is making me a little nervous, since the expected FG is around 1.012. I mashed in at the recommended temperature which was 151, and by the end it might have been around 149, which I know is a reason for having this low of an FG, but come on! I tried drinking it, and I mean it tasted okay, but it had no body what so ever, which is exactly how my first all grain beer was like. Having more of a body was something that I had hoped to do better on. I did make a starter, and I reused WLP001 yeast that I had. Is it possible that the sample I got from my bucket was lower than average, or should fermentation have stirred everything up? I'm pretty sure my hydrometer is calibrated correctly too.

My OG was 1.051, when the expected was supposed to be 1.054. Fermentation temperature has been 70-72 (this is what the sticker was telling me, is the beer actually warmer than what it says?).

 

[BeerJorge]

There's a few things that stand out right away... first is being that this is only your third batch, I must ask if you've calibrated your thermometer... I used three different thermometers and the difference in readings was 10 F!!

So that's the first thing to check...

Next is 1.004 is pretty low and I wonder if you have wild yeast eating up sugars... you normally don't need to do a yeast starter if you are re-using yeast within a few days (no more than a week)... if your gravity keeps dropping or your beer starts to fizz up, then that may be it, and if that's the case I would look into your cleaning and sanitizing for both brewing and collecting/storing yeast...

This may help: How To Calibrate Your Thermometer

 

[LarsonLE]

There's a few things that stand out right away... first is being that this is only your third batch, I must ask if you've calibrated your thermometer... I used three different thermometers and the difference in readings was 10 F!!

So that's the first thing to check...

Next is 1.004 is pretty low and I wonder if you have wild yeast eating up sugars... you normally don't need to do a yeast starter if you are re-using yeast within a few days (no more than a week)... if your gravity keeps dropping or your beer starts to fizz up, then that may be it, and if that's the case I would look into your cleaning and sanitizing for both brewing and collecting/storing yeast...

This may help: How To Calibrate Your Thermometer

Before I started brewing that day, I headed to wal-mart to grab a cheap $10 digital thermometer. When I got home, I made sure to "calibrate" it, by doing the ice bath method. I was getting a reading of 32 degrees, so I thought I was okay, but after viewing that video, I'm not sure now.

I have been reading about the wild yeast thing, and I'm not really tasting any off-flavors with these samples.

 

[Rundownhouse]

If you didn't knock all of the CO2 out of the sample you took, you'll get an artificially low FG reading. I don't know about eight points, but it'll be off.

 

[rjschroed]

1) mashing low is going to creat more fermentables. To that extreme, I don't think so but I'll let others chime in with their opinion on that.

2) If the sticker says 70-72 I bet it's been warmer than that. I try not to let my beers ferment over 66 and thats in a water bath to help control the temp by adding ice bottles and termal mass sitting in front of an AC unit. I don't have a lot of experience with WLP001 but if it is like US-05 like I've read then my guess is that a cleaner flavor would be produced by fermenting a little cooler (mid 60s)

 

[LarsonLE]

So I just took another hydrometer reading and I am still getting a reading of 1.004-1.005. One other thing though, I wanted to see if my hydrometer is calibrated correctly, so I took a reading of my tap water, and I got something like 0.995. I know distilled water is suppose to have a reading of 1.000, but should my tap water be that far off, or is my hydrometer messed up? I know this may sound funny, but I do not have access to distilled water. My refrigerator is old and doesn't have a water dispenser, and I do not have any bottled water (girlfriend had the last one today). It's really frustrating.

 

[erikhild59]

Sounds like you need a new hydrometer.

 

[LarsonLE]

Sounds like you need a new hydrometer.

I really hope so. Although I don't understand how a hydrometer would just stop performing correctly. The paper inside seems to be where it should be.

 

[rjschroed]

Most hydrometers are calibrated at 60 F so that is something else you might take into account. It's almost a trivial amounts at room temp but if your trying to be absolutely accurate you might want to consider that. I can get distilled water around here for under $1 a gallon and usually keep a gallon on hand to make sure my hydrometer is reading accurate (at least at 1.000) every time I use it. Cheap insurance. I hope your hydrometer was the issue. Your tap water, depending on its make up (chlorides, etc) won't necessarily read 1.000. For example, the tap water here is really high in chlorides and fluorides, I'd never use is for brewing, won't even drink it right out of the tap, my hydrometer reads .996 in it. Also, there is a difference between tap water, filtered water, bottled water and distilled water. Distilled water is supposed to be absolutely pure H20, no other minerals or otherwise in it. All the rest have other stuff in it for reasons like taste and sanitation. They really don't sell distilled water at the grocery store in NC?

 

[LarsonLE]

Most hydrometers are calibrated at 60 F so that is something else you might take into account. It's almost a trivial amounts at room temp but if your trying to be absolutely accurate you might want to consider that. I can get distilled water around here for under $1 a gallon and usually keep a gallon on hand to make sure my hydrometer is reading accurate (at least at 1.000) every time I use it. Cheap insurance. I hope your hydrometer was the issue. Your tap water, depending on its make up (chlorides, etc) won't necessarily read 1.000. For example, the tap water here is really high in chlorides and fluorides, I'd never use is for brewing, won't even drink it right out of the tap, my hydrometer reads .996 in it. Also, there is a difference between tap water, filtered water, bottled water and distilled water. Distilled water is supposed to be absolutely pure H20, no other minerals or otherwise in it. All the rest have other stuff in it for reasons like taste and sanitation. They really don't sell distilled water at the grocery store in NC?

No, they do. I will pick some up next time I'm there. I wrote that post late last night, so I couldn't really go out and pick some up.