Underpitching yeast

[waitej02]

I have been brewing for close to 10 years and have brewed 100+ batches. If I am not reusing yeast, I have always pitched 1 vial, smackpack or dry packet for 5 gallons (yield-about 5.5 into the carboy). 90% of what I brew are hoppy beers 6.5-7.5%. My son sent me a yeast calculator as we were brewing the last batch and it appears that 1 dry pack (04 or 05) only does maybe 4-4.5%.

All batches (prior was 6.5 with FG 1.012 in 16 days at 66F) hit FG <1.015. I have given several beers to professional brewers and never have been given feedback on off flavors from stressed yeast. What flavor characteristics should I be worried about?

 

[Cartman98]

I’ve never had an issue with underpitching with liquid yeast. Only time I’ve had issues was with US-05 dry. In those cases my FG was way too high so it was obvious what the problem was.

 

[ESBrewer]

What flavor characteristics should I be worried about?

Only severe under pitching tend to cause high terminal gravities or problematic contaminations. But you may get more off flavors such as esters, fusels and even diacetyl. But it depends on the type of yeast and conditions whether u will notice the difference. Below there is a link that describes it in more detail.
https://wyeastlab.com/pitch-rates

 

[dmtaylor]

Underpitching can lead to contamination (variety of weird flavors) and acetaldehyde (apple, latex, pumpkin). If you're not experiencing long lag times >24 hours, no contamination or odd apple-like flavors, then either you are not actually underpitching despite what anyone else tells you, or hops are covering up any off-flavors.

 

[waitej02]

Underpitching can lead to contamination (variety of weird flavors) and acetaldehyde (apple, latex, pumpkin). If you're not experiencing long lag times >24 hours, no contamination or odd apple-like flavors, then either you are not actually underpitching despite what anyone else tells you, or hops are covering up any off-flavors.

No long lag times. I’ll look for the apple-like flavor. Since they are hoppy, they may be less noticeable (covered up as you said).

Do most people pitch 2 packs of dry yeast?

 

[myndflyte]

If I'm using dry yeast, I'll pitch 2 packs since they are normally cheap enough. That being said I don't typically rehydrate so that's another reason why I pitch 2. As for liquid yeast, If it's anything in the range of 1.05, I'll just pitch the one vial/bag of liquid yeast, given that it's not too old. I've gone up to 1.070 and been fine with 1 bag of yeast, but it took off within 24 hours so I wasn't concerned and it was NEIPA so any off flavors may be drowned out by hops.

For a few upcoming porters and stouts that are higher up there in gravity, I will be making starters just because they will have a bit higher gravity and I want to make sure they ferment clean. I don't want a green apple coffee flavor coming through.

 

[corax]

In the past I've always been in the "more is better" camp, but my thoughts are changing.

The way I'm thinking now, if I just want to emphasize hops and/or malt, and don't care about any yeast-specific character (esters, phenolics, higher alcohols, etc), then I'll want to over-pitch a cheap, clean-burning, dry yeast (eg, 2 packs for a 5 gallon batch).

If I do want yeast character, then I'll want to under-pitch with 1 pack of the appropriate liquid yeast and no starter.

 

[dmtaylor]

Do most people pitch 2 packs of dry yeast?

No. I personally would only use 1/2 pack dry yeast for 5 gallons.