Flat Beer

[Vlint]

I've been getting flat beer and weak head retention in my last 3 batches. Could this a result of under pitching yeast? I use the northern brewer sugar calculator, so I don't think that is an issue. I never do starters and haven't had carbonation issues up to this point. I normally pitch liquid Wyeast packs. I sanitize with star San and clean all my buckets with PBW. Thoughts? Thanks

 

[biodarwin]

What kind of gravity are we talking about for these beers and how long are you letting it carb?

 

[Vlint]

Normal ale range. 1050's OG to 1012 FG. I usually sample one after a week to 2 weeks. Even after a month plus there's not a lot of carbonation change.

 

[boydster]

Underpitching can cause issues like you describe, but I wouldn't expect that in a 1.050 beer. What temperature are you storing the bottles at? 3 weeks at 70° F is the usual rule of thumb, and lower temps mean longer conditioning periods.

Also, you should consider making starters with liquid yeast

 

[SpeedYellow]

One thing I've learned on HBT is that underpitching yeast seems to cause 99.9% of people's problems.

/sarcasm

 

[Vlint]

I store them at about 67. I'll definitely be doing a starter next time

 

[Yooper]

I use the northern brewer sugar calculator, so I don't think that is an issue.

Probably that. I hate those calculators!

If you're using a normal amount of corn sugar, say 4-5 ounces by weight per 5 gallons of finished beer, they should carb up.

Less than that, you can expect some flat (or flat-ish) beer.

 

[Randy64]

1.05 to 1.012 your yeast finished its job. I wouldnt worry about making a starter unless your brewing a 1.07 beer or bigger. Make sure you are using the correct amount of priming sugar, and gently mix it into your beer to be bottled. Ive had bottles that are flat and others that gush foam, bottled from the same bucket, mixing the sugar in is very important.

 

[Randy64]

One thing I've learned on HBT is that underpitching yeast seems to cause 99.9% of people's problems.

/sarcasm

Missed the sarcasm tag at first and thought bad things about you. I couldn't agree more.

 

[boydster]

1.05 to 1.012 your yeast finished its job. I wouldnt worry about making a starter unless your brewing a 1.07 beer or bigger.

?

OP, just check a pitch rate calc like Mr. Malty or Yeastcalc and you will know when to make a starter. Or read a brew science book and do the calculation yourself if you don't trust those... Suffice to say that for a 5 gal batch, it's before you hit 1.070. Just because the yeast makes it to a reasonable FG doesn't mean the pitch rate was ideal or the fermentation was the healthiest.

Just for a point of reference, a 5 gallon batch of 1.050 beer should have either 2 smack packs or vials, or a ~1.5L starter.

I'm not saying pitch rate is the issue. But the beer was underpitched. That said, there is something else going on.