Why start with less yeast?

[olie]

TL;DR: I'm wondering why a recipe might suggest starting with less-than-I'd-a-guessed yeast and if there's any harm in starting with more.


Now that y'all so kindly explained why it's not a great idea to try to jump-start your brew with too little yeast [Splain To Me...], I get to my next recipe (a steeped-grains porter) and see that it suggests using a liquid yeast ("American Ale (liquid)"). Ok, this guy's (John Palmer) the expert, but I was taken to understand that liquid yeasts are typically much lower spore count than dried packets.

NOTE: I'm not looking for alterations to this recipe! I'm trying to understand why it is the way it is.

Q1: Why might this recipe suggest a liquid yeast?
Q1b: Is there a reason it might be better to start with a lower spore count?

Q2: Is there any harm in using-up one of the many packets of dried yeast that I already have, instead?

Thanks!

 

[chickypad]

I don't see anywhere on the recipe it says to pitch at a lower count, it just states what yeast to use. Many folks do yeast starters with liquid yeast to get pitch rate they want - especially with bigger beers, less than fresh yeast, etc. If you don't want to use starters, or you are otherwise worried about yeast health, then you can sub in a similar dry yeast especially for this particular style which is just using a neutral ale yeast.

 

[beermanpete]

Another possibility is that the desired yeast was not available in dry form at the time.

 

[olie]

Elsewhere in the book, he talks about how liquid yeasts are generally less desirable because they contain 25-50% the yeast cell count of dry packets. In the build-up of this recipe, he doesn't talk about making a starter and growing a stronger culture.

As I said above, I'm not looking for variations on the recipe; I'm trying to learn from what he's saying -- what is he saying here, and why is he saying it?

(Well, and the Q2: because I got curious about if there's any harm to starting with "too much" yeast. Ignoring this particular recipe, what is the impact if I just start whatever-batch with 4 packets of yeast (if it calls for 1)? Does that do anything to the resulting beer?)

 

[chickypad]

I'm looking in the new version of the book but it looks like the section you have linked there is about steeping specialty grains. The focus is not on yeast, he just lists an example recipe to illustrate things. Most of the time when people post or print a recipe they don't spell out every little thing out about their process, including things like pitch rate. It's up to you to decide what you want to do with that. There is a chapter in HTB about yeast, pitch rates, and a blurb about possibly increasing esters with underpitching. If you want more detail the book Yeast by Chris White and Jamil is a good one.

Re: your second question there's generally a lot less effect from overpitching then underpitching in terms of finished product, at least on the homebrew scale. Unless you're really trying to fine tune a yeast character (say with a German hefeweizen yeast or something) then I wouldn't worry too much about over pitching. Though why you would waste 4 dry packets on a batch I don't know.

 

[olie]

Yeah, this section is definitely all about steeping grains. The general progression is: fundamentals, all extract walkthrough, steeped walkthrough, all grain walkthrough. Then some stuff about debugging, experimenting, etc.

Book Yeast: Yeah, recommended by others earlier; on order

I get that the focus of this recipe isn't on the yeast, I'm just curious why he might have selected that, especially when, in an earlier chapter, he talked about liquid yeasts being lower count (so more difficult to work with). Maybe the intent was sort of textbook-style and I was supposed to remember that and then think to myself that I need to do a little starter without being reminded. Seems out of character for the book, though, which contains a fair amount of hand-holding, step-by-step, "I will organize this in such a way that you can't fail"-style.

Anyway, it mostly just got me to noodling. I anticipate many years of exploring, experimenting and learning, but I'm trying to make sure that I don't miss any early-on lessons and have to bang my head against any unnecessary walls.

(My natural tendency when learning is to find some unrelated wall to bang my head against for a while so, when I think I might be doing that, I like to check-in with folks who have perspective to see if I can save some wear on the bricks )

(I'm also one of those people who doesn't believe there's any "magic" to brewing -- it's just O-Chem, dammit*! -- so, when something seems too mysterious to me, I tend to Rottweiler into it until I get it unraveled.)

(*Artistry and craftsmanship to be sure! But it's not magic; it's just science. Science done well in the hands of artisans & craftsmen, so as to give the illusion of magic to outsiders. IMO, of course.)

 

[olie]

So, bottom line, what I'm hearing from y'all is...

A1: No particular reason. Author may have just been trying to change things up a bit.
A1b: No benefit. Author may or may not have intended that reader infer making a starter. (Unclear.)

A2: No particular harm, just a waste of yeast.

Sound about right?

 

[chickypad]

So, bottom line, what I'm hearing from y'all is...

A1: No particular reason. Author may have just been trying to change things up a bit.
A1b: No benefit. Author may or may not have intended that reader infer making a starter. (Unclear.)

A2: No particular harm, just a waste of yeast.

Sound about right?

Yes. I wouldn't read too much into it, I honestly think he just pulled a recipe and wasn't really focusing on yeast. In the later additions of the book there is a whole separate chapter on yeast and he doesn't really stress that dry is easier than liquid, just that dry will store longer. You do have to pay more attention to age/health of liquid yeast but it's not that difficult. In fact looking at that recipe again you could just pitch a relatively new package or vial of yeast directly without a starter, it's only 1.048 OG.

 

[olie]

Ok, thx. One of the reasons it struck me was, my 1st yeast purchase (for beer) was a 12-pack, thinking "well, if I'm going to get into this, I may's well stock up...", and I know it keeps fairly well in the fridge, but not forever so, in the back of my mind, I was thinking "oh great, now we're going to switch things up...?!

Since then, I've learned about ale vs lager yeasts and a few other things, and the Yeast book is on the way, but I'm still hoping not to have to trash-bin too much "brand new" materials. (I figure I'll have plenty of opportunity to bin my mistakes, no need to add "still in the original wrapper" stuff to the pile!)

Thanks!

 

[chickypad]

It will keep at least a couple years. What strain is it?

 

[olie]

Oh I know it's good for quite a while; was just exposing some of the stuff bouncing around in the back of my head. It's quite a mess back there!

My current over-supply is of SafeAle S-33 (Fermentis?), which has a best-before date of Feb-2020. I intend to use it all well before the end of next year, so that's all fine.

Again, I'm just noodling about this stuff. I tend to do that...

 

[ESBrewer]

"Pitch rates make a dramatic difference in the final flavor and aroma profile of any beer. Ester production is directly related to yeast growth as are most other flavor and aroma compounds.

A low pitch rate can lead to:

• Excess levels of diacetyl
• Increase in higher/fusel alcohol formation
• Increase in ester formation
• Increase in volatile sulfur compounds
• High terminal gravities
• Stuck fermentations
• Increased risk of infection

High pitch rates can lead to:

• Very low ester production
• Very fast fermentations
• Thin or lacking body/mouthfeel
• Autolysis (Yeasty flavors due to lysing of cells)"

source: Wyeast / wyeastlab.com

In other words, pitch rate (too low or way too high) may alter the taste.

 

[madscientist451]

T

Q1: Why might this recipe suggest a liquid yeast?
Q1b: Is there a reason it might be better to start with a lower spore count?

Q2: Is there any harm in using-up one of the many packets of dried yeast that I already have, instead?

Thanks!

1: Dry yeasts are fine, but as you brew more you might want to change it up and see if you like some of different yeasts that are available.

1B: Yes, you can get different yeast character if you underpitch the yeast, some brewers will do this when making a Hefeweizen to get more Banana flavor/aroma, but others say this is not the best way to do accomplish that.

2: Go ahead and substitute the yeast you have if its right for the style, for American ale, I'd use dry US-05.

Under pitching your yeast can cause some problems, but new brewers usually have other problems including sanitation, no temperature control, poor recipe selection or no recipe, just winging it, improper mash temp or temperature swings, or problems with bottling.
Using an established recipe and a pack of dry yeast is fine, as long as you have a good fermentation temperature.

Don't be afraid to save your yeast and re-pitch it. After you siphon the beer out of the carboy, swirl the remaining beer and yeast around and pout it off into a sanitized quart mason jar. Keep it in the fridge and use about 1/2 the jar on the next batch.

 

[RM-MN]

Fermentis says that their dry yeast has no diminishment in the dry yeast in 2 year of storage. If it doesn't degrade in 2 years, it probably doesn't degrade a significant amount in 3 years either.

Pitch rate is much discussed. There is a perfect pitch rate. Getting away from this a small amount will make you virtually the same beer. You have to deviate a fairly large amount before you can taste the difference. Stop worrying and make beer.