Isolated Yeast (Tree House): How to Identify and Characterize?

[couchsending]

Maybe they use dry yeast as their dry hopping regimen doesn't allow them to re-pitch yeast. Dry is a much more cost effective solution if this is the case...

 

[isomerization]

What is the purity of a brick of S-04. To make it simplistic let's say they use 1000 gram bricks. If it's 95% pure and the rest is others, will 50 grams of other yeast be enough to change the character of a beer? Maybe that's why temp control is key?

I know this will add tons of variables with which we think Nate does not appreciate, but it could explain why some beers have all three strains and the others only have two??

I could be way off... Just trying to think this through

I can't imagine the contamination would be anywhere near that high (I'd guess < 0.1% or 1 gm in a 1000 gm brick). That would be terrible practice. Anyone know if yeast labs are subject to FDA regulations? If so, then you can almost guarantee the contamination is coming from somewhere else.

With the possibility of a brick of s-04 not being 100% pure, what would the other yeast in there be? Could it be anything? Could it be wb-06 and t-58? Maybe they're just using s04 and the tests made by isomerization are picking up those "other" yeasts. It could be that TH doesn't even blend! Who knows... at the end of the day we just have to keep experimenting.

The only thing that can be said with (near) absolute certainty, is that different yeast strains end up in the TH cans. The why/how/when, can't be answered though (the what is speculative but substantial imo).

 

[Dog House Brew]

I can't imagine the contamination would be anywhere near that high (I'd guess < 0.1% or 1 gm in a 1000 gm brick). That would be terrible practice. Anyone know if yeast labs are subject to FDA regulations? If so, then you can almost guarantee the contamination is coming from somewhere else.



The only thing that can be said with (near) absolute certainty, is that different yeast strains end up in the TH cans. The why/how/when, can't be answered though (the what is speculative but substantial imo).

Agreed

 

[Sbe2]

I can't imagine the contamination would be anywhere near that high (I'd guess < 0.1% or 1 gm in a 1000 gm brick). That would be terrible practice. Anyone know if yeast labs are subject to FDA regulations? If so, then you can almost guarantee the contamination is coming from somewhere else.



The only thing that can be said with (near) absolute certainty, is that different yeast strains end up in the TH cans. The why/how/when, can't be answered though (the what is speculative but substantial imo).

That's why I ask.

Has anyone tested Bright? I can't remember what was tested, it is an outlier in the fact that they describe it as "fermented with a clean American Ale" yeast. If I am not mistaken, S-04 is an English strain.

 

[couchsending]

Bright has to be S-05/001/1056

 

[Jmash]

So I just transferred the latest batch (s-04 85%/T-58 etc..) into the dry hop keg for 2nd dry hop. Gravity 1.014 from 1.072 OG. Citra/Mosaic/Simcoe cryohops 2:1:1

Getting a bit of that Belgian floral/clove taste. Not crazy about it. Hopefully the 2nd dryhop addition helps mask it.

 

[SanPancho]

I can't imagine the contamination would be anywhere near that high

fermentis has their microbial data right there on the cut sheet/info page for each strain under "Typical Analysis"

 

[isomerization]

fermentis has their microbial data right there on the cut sheet/info page for each strain under "Typical Analysis"

Would have been helpful to just post it, but was an easy find...

So less than 1 yeast per 6 million of the intended yeast. Yeah, that would never be detected in a finished can. Of course the caveat is, is that correct.

Again, if anyone has actual data (not just anecdotal) on dry yeast contamination, I'd love to see it. It needs to be fresh yeast, not something that's gone through a round of growth/fermentation.

 

[savylemons]

It is seems it is much different - the yeast blends are all coming off too spicy/phenolic or tart - neither of which are things I detect in treehouse beers. The only non-Enlgish character I get is bubblegum, but surprisingly, that has been detected in our house IPAs from time to time during bi-monthly employee sensory.

The data I have is mainly from our own plates - we have been using S-04 for our hoppy beers for over a year now (we originally used wlp007 but found S-04 better for our hoppy beers... and cheaper). Generally we plate our FVs on day 5 of fermentation - at about generation 3 we start to see other yeast morphologies start to pop up - we have not bothered to get these other yeasts sequenced...yet.

Also, a good friend who works at a renowned QA lab in town for the alcohol industry (think of any major brewery/distillery and they have very likely used his company to do QA/QC work) has confirmed fresh bricks of S-05 to be unpure - I can only assume S-04 would be the same.

I don't know Nate or much about him, but I would be surprised if he did not harvest and repitch any of his yeast. I don't know of any other major brewery that doesn't practice this, but maybe that's whats so special about TH!

Like I said, I'm not convinced it's an actual blend - But who knows! I'm wrong about a lot of things but always trying to learn and that's why I still come to these forums and participate in awesome threads like this.

Somewhat off topic...but what temp and pitch rate do you have success with s04 at your brewery? I've given it a couple shots lately and have not enjoyed the results. I can confirm getting bubblegum esters from it alone as well, i just find s04 to really dull down the hop flavors and aroma and enhance the breadiness compared to other strains...but I'd give it another shot.

 

[NJGeorge]

Another thing to think about and an observation I have made. Do you think natural carbing in the keg at room temperature dulls the hoppiness of the beer at all? Ive noticed an IPA I naturally carbed isn't as hoppy as others that I have forced carbed in a few days. Could this be due to keeping it at a warm temp for a week? I will be kegging tomorrow and will give the natural carb another go as the bubbles are so much finer and stick around longer.

 

[isomerization]

Another thing to think about and an observation I have made. Do you think natural carbing in the keg at room temperature dulls the hoppiness of the beer at all? Ive noticed an IPA I naturally carbed isn't as hoppy as others that I have forced carbed in a few days. COuld this be due to keeping it at warm a warm temp for a week? I will be kegging tomorrow and will give the natural carb another go as the bubbles much finer and stick around longer.

Everyone's got different practices, but I have not found the keg conditioning to reduce hoppiness (haven't done a side-by-side though). This is anecdotal on my part, but I felt the hoppiness lasted longer, the beer was closer to yellow in color and the mouthfeel was slightly softer. These could all be confirmation bias, but I definitely didn't ruin my beers. Did save some CO2 though :rockin:

 

[SanPancho]

Would have been helpful to just post it, but was an easy find...

try reading posts on an iphone 5s with a cracked screen. lucky i could post anything at all.

 

[ThePaleAleIndian]

I am naturally carbing my attempt with gyle and CBC-1 right now as well. 4 days in the keg and it is sitting at just under 30 psi at room temp.

I will update you guys in a few days.

 

[overthebarsbrewing]

fwiw, I have yet to get any fruit, juice or Tree House character from T-58. Maybe someone can chime in on what temp got them there. I'm pretty dubious tbh. My most serious attempt was S-04 and T-58 with Comet single hop. I thought it was too thin and didn't notice T-58 giving me anything that I particularly wanted. The caveat is that Comet is a crazy hop, and it may not jive well with that yeast combo

I have a CBC-carbed Citra/Galaxy 6%ABV/70IBU NE Pale Ale now on tap that I made with 6g S-04 / 2g T-58 (75%/25% ratio) deliberately underpitched and fermented at ~75F. I used a simplified grainbill vs. my usual NEIPAs (85% Two-row, 10% Cara-Pils, 3% Honey malt, 2% Acid Malt), omitting Oats & White Wheat.

It has a phenomenal mouthfeel for a 6% ABV Pale Ale...better than TH Lights On, IMHO. It throws an amazing aroma, and taste is phenomenal...not belgiany at all.

FWIW...

 

[overthebarsbrewing]

Anyways, I have personally stuck with using 1318 sans temp control (peak temps around 74-76) as I enjoy the final product immensely. I do plan to come back to testing these yeast (I like the idea of dry yeast v. dealing with starters and harvesting yeast).

My best NEIPA that I've made to date was during my 3-way split batch experiment described ~10pgs back. It was the Citra-Mosaic done with 1318, fermented at ~75F and CBC-1 carbed. That thing was friggen' amazing. And I'm usually very over-humble and hyper-critical when it comes to assessing my homebrews.

I have 10 more gallons of it fermenting now.

 

[skibb]

Somewhat off topic...but what temp and pitch rate do you have success with s04 at your brewery? I've given it a couple shots lately and have not enjoyed the results. I can confirm getting bubblegum esters from it alone as well, i just find s04 to really dull down the hop flavors and aroma and enhance the breadiness compared to other strains...but I'd give it another shot.

For my IPAs I pitch at 1,000,000 cells/ml/degree plato - growth phase usually last about 6-8 hours before I start to get bubbles. My OG's are usually around 15-16 P

I pitch and ferment at 66 F. When it's about 3 P from terminal I raise the set-point on FV to 70 F, which it usually carries itself up to in the next 24 hours

 

[NJGeorge]

Everyone's got different practices, but I have not found the keg conditioning to reduce hoppiness (haven't done a side-by-side though). This is anecdotal on my part, but I felt the hoppiness lasted longer, the beer was closer to yellow in color and the mouthfeel was slightly softer. These could all be confirmation bias, but I definitely didn't ruin my beers. Did save some CO2 though :rockin:

Just curious, did you cold crash your beer?

 

[isomerization]

I am naturally carbing my attempt with gyle and CBC-1 right now as well. 4 days in the keg and it is sitting at just under 30 psi at room temp.

I will update you guys in a few days.

Nice! My attempts so far have been with residual yeast after a "cool crash" (50F for 24 hr drops hop matter), and have taken between 5-7 days to hit final psi at RT.

Just curious, did you cold crash your beer?

See above. My goal is to drop enough debris to easily close transfer. You can monitor your blowoff tube to see if any suckback is occurring. I don't subscribe to the theory that you have to "shock" the liquid by crashing fast.

My best NEIPA that I've made to date was during my 3-way split batch experiment described ~10pgs back. It was the Citra-Mosaic done with 1318, fermented at ~75F and CBC-1 carbed. That thing was friggen' amazing. And I'm usually very over-humble and hyper-critical when it comes to assessing my homebrews.

I have 10 more gallons of it fermenting now.

Awesome! Citra/Mosaic is def a fav, and pretty cost effective for hops these days. I haven't tried CBC-1 yet, how many g/gallon are you using? And rehydrated or sprinkled?

 

[ThePaleAleIndian]

Nice! My attempts so far have been with residual yeast after a "cool crash" (50F for 24 hr drops hop matter), and have taken between 5-7 days to hit final psi at RT.



See above. My goal is to drop enough debris to easily close transfer. You can monitor your blowoff tube to see if any suckback is occurring. I don't subscribe to the theory that you have to "shock" the liquid by crashing fast.



Awesome! Citra/Mosaic is def a fav, and pretty cost effective for hops these days. I haven't tried CBC-1 yet, how many g/gallon are you using? And rehydrated or sprinkled?

Cool. I'll have to try the 50F thing some time. I usually cold crash at 37F. For this one I filled a party balloon with CO2 to deal with the suckback. First time doing that, don't know if I'm just wasting CO2 haha. I think only going to 50F would help me stop worrying about suckback.

I used 2 g of CBC-1 for 5 gallons, primed the keg with wort I saved from brewday instead of dextrose or other sugar. Sprinkled it right in on top of the priming wort and some bagged/weighted keg hops, then purged the keg and CO2 transferred from my primary carboy. This was a primary ferment with 11.5 g S-04, 1 g WB-06, 0.9 g T-58.

 

[TheHairyHop]

I have a CBC-carbed Citra/Galaxy 6%ABV/70IBU NE Pale Ale now on tap that I made with 6g S-04 / 2g T-58 (75%/25% ratio) deliberately underpitched and fermented at ~75F. I used a simplified grainbill vs. my usual NEIPAs (85% Two-row, 10% Cara-Pils, 3% Honey malt, 2% Acid Malt), omitting Oats & White Wheat.

It has a phenomenal mouthfeel for a 6% ABV Pale Ale...better than TH Lights On, IMHO. It throws an amazing aroma, and taste is phenomenal...not belgiany at all.

FWIW...

I think that carbing with CBC really helps the mouthfeel. My T-58 batch was force carbonated.

Also, my Ariana single hop beer has taken a tropical spin since I carbed with a mix of yeasts. I think that I'll be doing this from now on. I haven't seen a reason not to

 

[TheHairyHop]

My only issue with naturally carbonating is that I'm left with an over pressurized keg that I either need to off gas or pour some foamy pints from. I'm very adverse to off gassing because I don't want to lose that aroma. Has anyone thought of a solution to this?

 

[TheHairyHop]

Good to know, thanks. Out of curiosity, what temp did you pitch/ferment that attempt at? Not sure if you already mentioned this in an earlier post, but how many total grams did you pitch into how many gallons?

I pitched at 78F and didn't temp control this one which is a departure from other NEIPAs I've done (all with 1318). In the past I have pitched 1318 at 60F and raised the temp to 72F over the first 72 hours. This one just sat at a pretty steady 72F ambient. I pitched 13.4 g total into ~6 gal for 5 gal kegged.

You know, the one other thing I was thinking is that I doughed in at about 100F and decoction mashed this one (I know, I know, but I do it pretty often because I enjoy it). But then I remembered reading a BYO article that said that a mash rest just above 100F can make ferulic acid, which is a precursor to the clove phenol. I definitely got a perceptible amount of clove on this one. I mean, it doesn't scream hef, but there's more of that than I wanted, and certainly more than in any Treehouse beer I've had. Single infusion next time I guess.

I don't have my notes on me, but I think that I pitched at 75 and fermented uncontrolled

 

[ThePaleAleIndian]

My only issue with naturally carbonating is that I'm left with an over pressurized keg that I either need to off gas or pour some foamy pints from. I'm very adverse to off gassing because I don't want to lose that aroma. Has anyone thought of a solution to this?

Yeah, I'm running into the same problem right now, my gauge is now pegged at just past 30 psi on my CBC-1 deal. This time I used the same amount of primer that I would have used to bottle condition. Next time I think I'll cut it down by a third or so. Seems like somewhere between almost flat beer out of primary and overcarbed there has to be a sweet spot. Just gotta find it!

 

[couchsending]

My only issue with naturally carbonating is that I'm left with an over pressurized keg that I either need to off gas or pour some foamy pints from. I'm very adverse to off gassing because I don't want to lose that aroma. Has anyone thought of a solution to this?

Why do you need to need to off gas it? After 5-7 days just put it in the keezer for 3 days or so and the head pressure will have dropped as more Co2 is absorbed into the beer at the colder temps. Head pressure should drop to normalish serving pressure after a while and beer should be fully carbed. I just put my spunding valve on it every now and again and monitor the psi. When it gets closer to typical serving/carbing pressure is when I hook a party tap up and blow off any sediment then hook up to taps and start drinking.

 

[Silver_Is_Money]

***DNA fingerprinting update***

New strains analyzed in the right gel (old gel on the left for comparison purposes). Strain 1 (WY1056) was used as a control of sorts.

New strains (all are dry yeasts):
12: S-04
13: S-05
14: S-23
15: Danstar Munich
16: W-34/70
17: T-58

Nice to see S-05 and WY1056 have a very similar banding pattern, although this just further reinforces the previous commentary that similar strains at the genetic level can produce differences at the phenotypic level (e.g. S-05 krausen behavior v. WY1056).

S-23 and W-34/70 have very similar banding patterns as well. I haven't used either yeast, so can't say much there...

***REQUEST***
I am interested in testing more yeast strains, and would be willing to mail autoclaved blotting paper foil packets (see here: http://suigenerisbrewing.blogspot.com/2017/03/new-mailer-system.html) to those with yeast strains I have not tested yet. Shoot me a PM if interested.

Which 'Danstar Munich' did you test as seen in #15 above? 'Classic' or 'Wheat'?

 

[Northern_Brewer]

I think that carbing with CBC really helps the mouthfeel. My T-58 batch was force carbonated.

Also, my Ariana single hop beer has taken a tropical spin since I carbed with a mix of yeasts. I think that I'll be doing this from now on. I haven't seen a reason not to

The CAMRA membership forms are here

 

[Jwin]

Yeah, I'm running into the same problem right now, my gauge is now pegged at just past 30 psi on my CBC-1 deal. This time I used the same amount of primer that I would have used to bottle condition. Next time I think I'll cut it down by a third or so. Seems like somewhere between almost flat beer out of primary and overcarbed there has to be a sweet spot. Just gotta find it!

If you are kegging at a week old, that's not flat beer. There is a lot of co2 in solution.
If you are cool/cold crashing, you are pulling more gas into solution.
Sooooo
You need less priming sugar or a better spunding rig.
With a spunding valve set correctly, your could use a half pound of priming sugar and be okay.
If you are just transferring the beer and sealing the keg, yeah, gonna be over carbed
The difference in bottling and this is:
A)when we bottled, we left our beers in primary a bit longer. It off gassed some.
B)when we bottled, we transferred into a bottling bucket, etc, and it off gassed.
Transferring under pressure doesn't allow gas (much) to escape.

In short, if u are sealing the keg, try 1/3 less priming sugar as stated.

Good luck and cheers!

 

[NJGeorge]

Just kegged this last night after one week in the fermenter at 75. Do not have the exact % of yeast as my scale doesn't measure grams in decimals (just ordered one). The main work horse was s-04 which was just under 5g for a 2.5 gal batch. T-58 and wb-04 I literally had to eye ball in 1/4 of a tsp. I know this has huge variables but I had no choice. This beer came out a little more Belgian/hefe than I wanted and expected. Any ideas? Too much of one of the yeasts? Too high of a temp? I'll see how this develops and naturally carbs (1g CBC, 1oz sugar) in the keg and will report back.

 

[thehaze]

Just kegged this last night after one week in the fermenter at 75. Do not have the exact % of yeast as my scale doesn't measure grams in decimals (just ordered one). The main work horse was s-04 which was just under 5g for a 2.5 gal batch. T-58 and wb-04 I literally had to eye ball in 1/4 of a tsp. I know this has huge variables but I had no choice. This beer came out a little more Belgian/hefe than I wanted and expected. Any ideas? Too much of one of the yeasts? Too high of a temp? I'll see how this develops and naturally carbs (1g CBC, 1oz sugar) in the keg and will report back.

Is the belgian/hefe character strong? Is it like a Duvel? Or like an Andechs/Schneider hefe? Or are those flavours more subtle?

How heavy did you dry hopped it? Maybe dry hop a bit more?

If you were to taste the beer for the first time or give it to some friends, that drink craft beer, what would you/they say?

But I am looking forward for your feedback once the beer is fully carbonated.

 

[Jwin]

I don't know if this was mentioned but, is there any chance that TH is blending two fermentations in the bright tank?
I could see the benefit of being able to produce a broader ester profile with different temps and pitch rates.
Half S04 underpitched and fermented warm
Half of the blend, regular pitch rate, fermented cool to keep the pepper and banana in check.

Just a thought.

 

[Northern_Brewer]

Just kegged this last night after one week in the fermenter at 75....T-58 and wb-04 I literally had to eye ball in 1/4 of a tsp...This beer came out a little more Belgian/hefe than I wanted and expected.

I'm not surprised after a week at 75F - pitch at that kind of temperature but let it fall to 66F or so and you should be OK, perhaps even drop it to 60F after high krausen.

 

[ThePaleAleIndian]

Just kegged this last night after one week in the fermenter at 75. Do not have the exact % of yeast as my scale doesn't measure grams in decimals (just ordered one). The main work horse was s-04 which was just under 5g for a 2.5 gal batch. T-58 and wb-04 I literally had to eye ball in 1/4 of a tsp. I know this has huge variables but I had no choice. This beer came out a little more Belgian/hefe than I wanted and expected. Any ideas? Too much of one of the yeasts? Too high of a temp? I'll see how this develops and naturally carbs (1g CBC, 1oz sugar) in the keg and will report back.

Sounds like you and I are very much in the same boat right now. I kegged a week ago today and it was much more hef-y than I would like. Didn't get a whole lot of bubblegum from the sample. This was a copitch of about 85/8/7% S-04/WB-06/T-58.

Right now my plan for next time, assuming it doesn't clean itself up as it's conditioning on the CBC-1, is to use S-04 as the only primary strain and condition with a mix of more T-58 than WB-06 (not sure what that means for the CBC-1). I also thought the S-04 dulled the hop character down quite a bit compared to other NEIPAs I've made with 1318, so my other plan for next time is to move a lot of my whirlpool addition to the wort that I use as priming sugar for keg conditioning.

On the hot side, I am planning to drop a low temp rest that I did on this one. According to a Beer and Wine Journal article a low temp rest just north of 100F can make a bunch of ferulic acid, which is a presursor to our dreaded clove phenol. I guess that change wouldn't necessarily be applicable to everyone.

This is that article: http://beerandwinejournal.com/german-wheat-beer-iii/

FWIW, I just had a Haze and a Green last night. I got some bubblegum from Green and a ton of flavor I associate with Galaxy hops. I definitely got banana from the Haze. But I didn't get any clove/pepper phenols from either, despite looking for them as I was drinking.

 

[ThePaleAleIndian]

If you are kegging at a week old, that's not flat beer. There is a lot of co2 in solution.
If you are cool/cold crashing, you are pulling more gas into solution.
Sooooo
You need less priming sugar or a better spunding rig.
With a spunding valve set correctly, your could use a half pound of priming sugar and be okay.
If you are just transferring the beer and sealing the keg, yeah, gonna be over carbed
The difference in bottling and this is:
A)when we bottled, we left our beers in primary a bit longer. It off gassed some.
B)when we bottled, we transferred into a bottling bucket, etc, and it off gassed.
Transferring under pressure doesn't allow gas (much) to escape.

In short, if u are sealing the keg, try 1/3 less priming sugar as stated.

Good luck and cheers!

Yeah, that's actually exactly what i did, kegged at a week post pitch and transferred under pressure. Although it was only like 2 psi because it was carboy to keg, but I guess any amount of pressure will keep that CO2 from coming out of solution. For previous NEIPAs I've done, I bottled at a week as well, but like you mentioned, I think the initial transfer to the bottling bucket allows for some off-gassing.

But yeah, agreed, about a third less primer is what I'm going to do next time.

Thanks!

 

[Sbe2]

I don't know if this was mentioned but, is there any chance that TH is blending two fermentations in the bright tank?
I could see the benefit of being able to produce a broader ester profile with different temps and pitch rates.
Half S04 underpitched and fermented warm
Half of the blend, regular pitch rate, fermented cool to keep the pepper and banana in check.

Just a thought.

Like a blended wine, I don't see why not unless Nate denied it on twitter.

 

[NJGeorge]

Is the belgian/hefe character strong? Is it like a Duvel? Or like an Andechs/Schneider hefe? Or are those flavours more subtle?

How heavy did you dry hopped it? Maybe dry hop a bit more?

If you were to taste the beer for the first time or give it to some friends, that drink craft beer, what would you/they say?

But I am looking forward for your feedback once the beer is fully carbonated.

It has the slightest hint of it and it's hard to pin point right now. Definitely not strong. It also had that tang acid taste. Don't have a bench mark, but it definitely has that character of a Belgian/hefe beer. Have to let it carbonate and see. Also one thing to note is the hops were a bit muted. I used 8oz total for a 2.5 gal batch. Half of that was for dry hops. Hard to say without it being carbonated, but if I were to try it for the fist time I would think it was a slight Belgian IPA. Dang it! Lol

 

[NJGeorge]

I'm not surprised after a week at 75F - pitch at that kind of temperature but let it fall to 66F or so and you should be OK, perhaps even drop it to 60F after high krausen.

Will definitely pitch warm and ferment cool next time in that temp range.

 

[TheHairyHop]

The CAMRA membership forms are here

The best vacation that I've ever had was a solo tour of Kent

 

[Jwin]

Like a blended wine, I don't see why not unless Nate denied it on twitter.

If anyone can find out the fermentor and bright tank sizes...
If the bright tank is much larger than the FV, there's definitely some blendng going on. Wether or not it's of the exact same beer, dunno.
Seems that once blended, some t58 might further attenuate a S04 only batch, scrubbing some o2 in the process.
All loose theory here.

 

[isomerization]

Which 'Danstar Munich' did you test as seen in #15 above? 'Classic' or 'Wheat'?

Wheat

It has the slightest hint of it and it's hard to pin point right now. Definitely not strong. It also had that tang acid taste. Don't have a bench mark, but it definitely has that character of a Belgian/hefe beer. Have to let it carbonate and see. Also one thing to note is the hops were a bit muted. I used 8oz total for a 2.5 gal batch. Half of that was for dry hops. Hard to say without it being carbonated, but if I were to try it for the fist time I would think it was a slight Belgian IPA. Dang it! Lol

Same thing happened with my attempt a couple months ago. Was my first time using any of the yeasts, so I didn't have a baseline expectation. I do feel like I've read a bunch of people mention that s-04 mutes yeast character, but there must be a way...

 

[TheHairyHop]

Like a blended wine, I don't see why not unless Nate denied it on twitter.

it's a long shot, but I've thought that they could have two fermenters. One is larger and is fermented with S04 and little to no hopping, the other is smaller and dry hopped to high hell, with estery yeasts used for oxygen scrubbing. Once purged of O2, the hopped wort/beer is pumped into the larger tank