Consistently low ABV...ideas?

[mherrbrew]

I have brewed 3 kits so far and the FG had been consistently higher than it should be. I'm only off by a few (ex. FG should be around 15 but it usually finishes around 18 or so). This, in turn causes the ABV to be lower than desired. OG is usually on point and temp is between 68-72 degrees. I store it under my bar so it's good and dark. I wait until it "stops" fermenting and then I give it a gentle stir then the FG drops a little and stalls again.

Any ideas on how to give my brew a little kick??

 

[Qhrumphf]

What's your pitching process and aeration method? Are you making starters or rehydrating dry yeast? And are you aerating your wort at all before you pitch?

Underpitching and insufficient aeration can both keep you from getting full attenuation.

 

[blizz81]

If you have a drill laying around, you could try getting a paint stir attachment to aerate your wort before pitching. Also make sure you are not underpitching on your yeast, though if you're doing normal extract kits in the 5-6% abv range and pitching, say, a packet of dried yeast, I think you should be fine.

 

[Pkrd]

1.018 isn't hugely different from 1.015, and extract tends to finish a little high. If you wan't a higher ABV you can add more sugars or less water to boost OG.
As usual, RDWHAHB.

 

[mherrbrew]

I usually use the yeast packet that comes with the kit. I make sure to spread the yeast across the entire surface of the fermentation bucket. After pouring the wort in, I usually add the water to make 5 gallons. I do it in a way that splashes and causes bubbles. Other than that I don't do anything special.

 

[Qhrumphf]

Yep, exactly what I figured

If you're not rehydrating your dry yeast, you should be. If dry yeast aren't rehydrated in water first, when you first add them to wort they can't regulate the sugar intake, and it ends up killing about half of your yeast, and you end up underpitching as a result. And with liquid yeast, unless you're brewing a session beer or a small batch, there's usually not enough yeast in a vial/smack pack for a full 5 gallons of normal gravity, and a starter is usually needed.

You'll find you get better results if you deliberately aerate your wort. There's a bunch of ways to do it, but simply pouring in a way that splashes isn't particularly effective. If you use multiple buckets and pour back and forth a few times, that's better. Or, if you transfer to the fermenter, seal it, and then shake it vigorously for a few minutes. But it's safest and easiest to just inject filtered air or pure oxygen via a diffusion stone (oxygen being the better of the two).

 

[witko]

A few batches ago I started aerating with a hand blender. After I take my OG reading and before I pitch my yeast I sit down with a hand blender (that's been sitting in sanitizer for 10 minutes) and mix things up for about 5 solid minutes. Just keeping moving it up and down and all around. The volume in the pail tends to come up by about 1/2", so to me that says there's a good volume of bubbles in there. I've noticed my fermentations have definitely been kicking off much much faster since doing that. Mind you I've also been making 1 liter starters for everything lately. Either way... seems to be much happier with those two changes.

 

[mherrbrew]

How would you suggest i rehydrate the dry yeast? I've never heard of doing that!

 

[guldalian]

To rehydrate:
1) boil 1-2 cups of water
2) cool to 95 F
3) sprinkle in yeast
4) after 10 min, gently stir
5) slowly cool to pitching temps
6) and pitch!

 

[mherrbrew]

This is why I love this forum! Thanks everyone for the help.

 

[zippyclown]

I have brewed 3 kits so far and the FG had been consistently higher than it should be. I'm only off by a few (ex. FG should be around 15 but it usually finishes around 18 or so). This, in turn causes the ABV to be lower than desired. OG is usually on point and temp is between 68-72 degrees. I store it under my bar so it's good and dark. I wait until it "stops" fermenting and then I give it a gentle stir then the FG drops a little and stalls again.

Any ideas on how to give my brew a little kick??

Aerate your wort, pitch enough yeast, and ferment at the right temperature.

 

[nthammer]

perhaps substitute a small amount of the extract for some other simple sugar, to encourage a lower FG.

I had issues with FG when I brewed extract on random batches. Now with allgrain I have not had the problem of under-attenuation, so i attribute the issues I had to extract being extract