London III vs. Juice

[ashopis]

Hey all,

I'm working up an experiment comparing two 2.5 gallon smash beers that differ only in yeast variety. One will get London III and the other Imperial Juice.

I know that the cell count in the two packets is different. London III has 100 billion cells and Juice has 200 billion. Is it a big deal if I just pitch a pack of each or will the differing pitch rate mess up my experiment?

Thanks and Cheers!

 

[BrewerBrad82]

For what its worth, 1318 and Juice are the same strain.

 

[ashopis]

For what its worth, 1318 and Juice are the same strain.

I've heard this. But I've also heard they produce different tasting beers. Wierd. That's one reason for the experiment.

 

[day_trippr]

fwiw, I used to ranch both A38 and 1318 but after six 10g batches split between them and not a soul could tell them apart I dropped the A38 and farm 1318.

If they're not exactly the same they're too close to tell apart. I've not read of anyone on HBT claiming otherwise...

Cheers!

 

[sweetcell]

Is it a big deal if I just pitch a pack of each or will the differing pitch rate mess up my experiment?

yes, it would be a big deal. if you want to compare apples to apples, you should pitch the same amount. this yeast (let's pretend they are the same, i can't tell them apart) contributes esters, which are generally produced during the growth phase.

the suggested pitch rate for 2.5 gallons of 1.060 wort is 105B cells. so assuming you got a super-fresh pack of 1318, you're good to go, while 200B from a pouch of Juice is way overpitching - you'll get almost no growth, so little to no esters. yeast also behaves differently when overpitched, so other fermentation characteristics like attenuation are likely to be different too.

 

[Dgallo]

while 200B from a pouch of Juice is way overpitching - you'll get almost no growth, so little to no esters. yeast also behaves differently when overpitched, so other fermentation characteristics like attenuation are likely to be different too.

Totally true about being the same strain. And the ester comment is true for a stander fermentation, however he can still get growth by manipulating fermentation temps. If he drops temps low in the beginning of ferm and slows the first 48 hours of fermentation he can still get a great ester profile with a higher pitch rate since the growth that will happen will happen over a longer period of time. That being said I personally prefer to under pitch and temp drive to stress the yeast during the growth phase. I feel the ester profile is more define doing it this way

 

[sweetcell]

can still get growth by manipulating fermentation temps. If he drops temps low in the beginning of ferm and slows the first 48 hours of fermentation he can still get a great ester profile with a higher pitch rate since the growth that will happen will happen over a longer period of time.

i'm not a yeast expert or microbiologist, i can only go with my experience and what i've read, but the above statement doesn't jive with what i know. low temps will lead to slower growth, but it doesn't lead to extra esters. in fact low temps = less growth = less esters. that's why lagers are fermented cold: to reduce esters.

 

[Dgallo]

i'm not a yeast expert or microbiologist, i can only go with my experience and what i've read, but the above statement doesn't jive with what i know. low temps will lead to slower growth, but it doesn't lead to extra esters. in fact low temps = less growth = less esters. that's why lagers are fermented cold: to reduce esters.

Esters are created in the growth phase so by forcing it to take longer The yeast produce more esters for a longer period of time. L3 is fermented at 63*f by many commercial breweries for this reason. Scott Janish explains this method at a 1.0 pitchrate in his book.

Also the OP pitching one pack of a38 at 1.060 with a pack is close to a month old pack is in the range for the ideal pitch rate for ester production

Regarding lagering, that’s completely different story. Those strains typically produce very little ester to begin with and they are fermented closer 50 to keep them as clean as possible. So that’s comparing apples to oranges.

 

[Beernik]

Ester production is increased when the yeast has to build more cell walls or is stressed. There are three main ways to increase water production:
1. Underpitch. If you underpitch, the yeast has to make more yeast, which means making more yeast cell walls.
2. Warmer temps. Warmer temps speed the fermentation rate, meaning yeast have to grow and reproduce faster, increasing the rate of cell wall growth.
3. Under-aerate. If you under-aerate, yeast will use all the DO to build yeast walls, encouraging the growth of ester forming enzymes.

All things being equal, for an English style, I’d use warmer temperatures for ester production rather than an underpitch.

And back to the original question, yes pitch rates can make a big difference in a side-by-side comparison even if they are both overpitches.

 

[sweetcell]

Esters are created in the growth phase so by forcing it to take longer The yeast produce more esters for a longer period of time.

again, this doesn't jive with anything i've read. esters are indeed created in the growth phase, but they are created by amount of growth (i.e. how many cells are created, how much cell division occurs) - not the speed or amount of time over which it happens.

if the optimal final number of cells for a batch is 400B, you'll have more esters with a 100B pitch (because it has to multiply 4 times) vs. pitching 200B which requires only a 2X growth factor. pitching warmer or cooler doesn't change the growth factors required of your pitch. if anything, a cooler pitch might make the yeast sluggish and cut down on how many times they divide - resulting in a cleaner, and possibly less attenuated, beer. (aside: this is why one waits a few days before starting to ramp up temps. by starting cooler you get fewer run-away esters and fusels. once the main growth phase is over, then you can increase temps with minimal impact on flavor profile)

but perhaps i haven't been reading the right sources... if you could point me to sources that describe cooler = more esters, i'd appreciate the opportunity to learn.

Regarding lagering, that’s completely different story. Those strains typically produce very little ester to begin with and they are fermented closer 50 to keep them as clean as possible. So that’s comparing apples to oranges.

lager yeast can produce esters - fewer than ale yeast, as a general rule, but they are not ester-free. try pitching a lager strain at 66*F - you'll get plenty of esters (re: california common), a lot more than what you'd get with an ale strain like chico.

as you note, cooler temps = fewer esters ("they are fermented closer 50 to keep them as clean as possible"). a difference between ale and lager strains is that most ale strains will not ferment well at 50 whereas lager yeast is happy at those temps. so another way of looking at it: to get fewer esters, ferment cooler; and to ferment cooler use a type of yeast that is happy when cool - AKA lager yeast. but perhaps you have information that contradicts this?

 

[duelerx]

I've heard this. But I've also heard they produce different tasting beers. Wierd. That's one reason for the experiment.

They are exactly the same, but Imperial yeasts pitching rates are higher because they use 200 billion pouches compared to the 100 billion of Wyeast, so it depends.