Over sized fermenter

[Merleti]

What are your thoughts on an over sized fermenter? Most seem to advise low head space. Most say to do it to reduce oxygen.
Does this really matter?
If it matters is the type of yeast the reason?
If it is from oxygen can you put a blanket of co2 in the fermenter 24 hrs later to avoid this or before(airated wort when pitching as always)?
If oxygen will harm fermentation then why does open fermentation work?

 

[Immocles]

I have fermented 2.5g inside of a 6g fermenter several times. The only time it didn’t work out so well was when I opened the vessel and dry hopped. Otherwise it worked just fine.

 

[Vale71]

If it is from oxygen can you put a blanket of co2 in the fermenter 24 hrs later to avoid this or before(airated wort when pitching as always)?

Unfortunately knitting with CO2 is a lost art...

 

[Merleti]

Vale71. Is it a lost art for a reason? Why should you or shouldn't you do this?

 

[3 Dawg Night]

Vale71. Is it a lost art for a reason? Why should you or shouldn't you do this?

Knitting. Blanket.

 

[Vale71]

Vale71. Is it a lost art for a reason? Why should you or shouldn't you do this?

Yes. The reason is that CO2 blankets do not exist, which I was trying to convey in a jestful manner...

 

[Merleti]

Ha I get it. I just thought it was a spell check.

 

[Mark3885]

I ferment 10 to 12 gallons in a half keg all the time , never had a problem .

 

[Nate R]

What are your thoughts on an over sized fermenter? Most seem to advise low head space. Most say to do it to reduce oxygen.
Does this really matter?
If it matters is the type of yeast the reason?
If it is from oxygen can you put a blanket of co2 in the fermenter 24 hrs later to avoid this or before(airated wort when pitching as always)?
If oxygen will harm fermentation then why does open fermentation work?

Not sure if this helps, but... if you are considering a large fermentor i would say just make sure it is pressure rated so you can safely purge with c02.
I think most folks would agree purging the headspace 2 to 3 times with c02 is effective before fermenting begins. Afterwards, especially with delicate hoppy beers, you dont want to purge anymore, so being able to keep it sealed is a key.

 

[Merleti]

Nate R would you want to purge after the first 24 of fermentation. Would it be counter productive to purge with co2 first and then airate your wort?

 

[Nate R]

Nate R would you want to purge after the first 24 of fermentation. Would it be counter productive to purge with co2 first and then aerate your wort?

Ooooo boy. That's a loaded question! I bet you will get as many answers as members here! Lol... Honestly- if you have a good sealed fermenter, you can trust the first purge. Here is my process. YMMV, and I think a lot of ways will work.
I have a Spike cf5 with temp control coil and glycol chiller.
#1: After I fill it with wort, I seal it up. I then immediately purge with c02. At least 3 times. (Note- If i had a pump, I could pump wort into it like a lot people here do.)
#2: I add about 5psi C02 and set the temp coil to the temp I want. (my wort comes in about 75-80 or so, It only takes about 15 minutes to reach desired temp- usually 68 or so)
#3: When I hit temp, I use the carb stone and blast it with Oxygen.
#4: I then open the 1.5" tri-clamp pressure gauge and dump in my yeast.
(Note- sometimes I will add yeast, then aerate, Again- many discussions to be had. )
#5- I will then purge again with c02 once.
#6- I will attache a blow-off tube and let the fermentation begin! Technically, there is a bit Oxygen in the head-space. I once decided to wait 12 hours for fermentation to start before adding the blow-off tube (so I could purge with c02 and ensure no oxygen). The problem with this is... I barely made it in time to add a blow-off tube. It is just not worth it to me.

Sorry, this is rambling. May I suggest you read some on this thread- it is about the Spike CF series, but a lot of handy info!

https://www.homebrewtalk.com/threads/spike-conical-observations-and-best-practices.645440/

 

[Merleti]

Nate R thank I will check out the Spike CF series thread. I tried google but I only get pages of adds. Googles not what it use to be on finding info.

 

[Nate R]

Nate R thank I will check out the Spike CF series thread. I tried google but I only get pages of adds. Googles not what it use to be on finding info.

Yup. There is a way to google just here, but I forgot it. Also- there are a few good tanks in this market. SS, Stout, Brewer's hardware... Blichammn, Morebeer. Pros and cons to all. Costs for sure. I would consider your all-in needs: Cooling, heating. Will you use Glycol or a unpright fridge/freezer? Expansion down the line? Dry hop? Etc. I am sure there are threads on SS and all the other models, too. Honestly that Spike thread refers to almost all others, too.

Good Luck!

 

[Merleti]

I picked up 2 -2bbl for $1400. I have a 1 bbl brewing system that I planned on doing double batches. If for some reason I cannot do a double batch I want to be prepared in advance.

 

[Nate R]

I picked up 2 -2bbl for $1400. I have a 1 bbl brewing system that I planned on doing double batches. If for some reason I cannot do a double batch I want to be prepared in advance.

That's some serious beer! You may want to seek some advice from big brewers, then... as I only do 5 gallons, it;s pretty small. But I would think no problem with even 60-70% extra head-space. Only thing is you will use more C02, but that is not really that expensive anyways.

 

[Gregory T]

What are your thoughts on an over sized fermenter? Most seem to advise low head space. Most say to do it to reduce oxygen.
Does this really matter?
If it matters is the type of yeast the reason?
If it is from oxygen can you put a blanket of co2 in the fermenter 24 hrs later to avoid this or before(airated wort when pitching as always)?
If oxygen will harm fermentation then why does open fermentation work?

I think it was from Brew Like a Monk, but when Trappists switched to conical fermenters they use roughly 1/2 the space deliberately

 

[Gregory T]

Not sure if this helps, but... if you are considering a large fermentor i would say just make sure it is pressure rated so you can safely purge with c02.
I think most folks would agree purging the headspace 2 to 3 times with c02 is effective before fermenting begins. Afterwards, especially with delicate hoppy beers, you dont want to purge anymore, so being able to keep it sealed is a key.

why purge O2 in a fermenter? yeast need oxygen at beginning of fermentation

 

[Nate R]

why purge O2 in a fermenter? yeast need oxygen at beginning of fermentation

Well, for me- again, others may vary- for me, I use a carb stone with compressed oxygen from a steel tank. So the oxygen is already dissolved in the wort. Because I do not have a yeast brink, and I must dump the yeast in the top port, I always purge the top layer with C02 just in case. An over-abundance of caution I am sure. But i've never had an infected batch! (I;ve made plenty of crappy beer, but that was on me and not because of an infection!)

 

[Merleti]

From what I read yes you want oxygen in the wort when pitching the yeast. I think we all do that and some that make big beers do it a second time at 12 to 18 hours after pitching. Nate like to pit co2 to help reduce infections. I am a little more concerned about the head space and oxidation after the lag phase is over.

 

[Nate R]

From what I read yes you want oxygen in the wort when pitching the yeast. I think we all do that and some that make big beers do it a second time at 12 to 18 hours after pitching. Nate like to pit co2 to help reduce infections. I am a little more concerned about the head space and oxidation after the lag phase is over.

So, if I think i get your question here... during the active fermentation phase, the fermentor is hooked up to either a blow-off tube or airlock. Again, a benefit of a closed pressurized system is you can spund as well. So this leaves the naturally made c02 in the head space. Or, what I usually do- after I remove blow-off tube, I will purge headspace with c02 again. This can all be done in a closed system, so really oxidation is not a factor.

 

[Merleti]

Nate I mainly make Ales so I wouldn't be spunding during fermentation.

So many people say never to use an over sized fermenter , but it seems like no one can give you a proven reason.

 

[Big Monk]

Nate I mainly make Ales so I wouldn't be spunding during fermentation.

So many people say never to use an over sized fermenter , but it seems like no one can give you a proven reason.

In the case of homebrew sized fermenters, it's really a "CYA" statement, i.e. why have the extra space if you don't need it. This is especially true when fermentation ceases activity and you don't want to have a larger amount of O2 in the headspace than is avoidable.

In a commercial brewery, and @Gregory T pointed out the example that immediately came to my mind (Rochefort in this case), they use oversized cylindro-conical vessels to alleviate head pressure and keep the required flavor profile of their beers.

 

[Gregory T]

In a commercial brewery, and @Gregory T pointed out the example that immediately came to my mind (Rochefort in this case), they use oversized cylindro-conical vessels to alleviate head pressure and keep the required flavor profile of their beers.

Rochefort..yum

 

[Merleti]

Thank you all for your input. Looks like I'll just have to experiment with different ways depending on different types of yeast and flavors that I like.

 

[Big Monk]

Thank you all for your input. Looks like I'll just have to experiment with different ways depending on different types of yeast and flavors that I like.

Take this with the grain of salt that all reasonable people should when I talk (), but of all the possibles "levers" (fermentation parameters) to pull, fermenter geometry is a genuinely useless one given the size of fermenters hoembrewers are using.

Temperature, Pitch rate, oxygenation, etc are all infinitely more tweak able and will yield actual results.

 

[Merleti]

Coolships definately blow the geometry of fermenters out of the water and they work.

 

[Andre3000]

Ooooo boy. That's a loaded question! I bet you will get as many answers as members here! Lol... Honestly- if you have a good sealed fermenter, you can trust the first purge. Here is my process. YMMV, and I think a lot of ways will work.
I have a Spike cf5 with temp control coil and glycol chiller.
#1: After I fill it with wort, I seal it up. I then immediately purge with c02. At least 3 times. (Note- If i had a pump, I could pump wort into it like a lot people here do.)
#2: I add about 5psi C02 and set the temp coil to the temp I want. (my wort comes in about 75-80 or so, It only takes about 15 minutes to reach desired temp- usually 68 or so)
#3: When I hit temp, I use the carb stone and blast it with Oxygen.
#4: I then open the 1.5" tri-clamp pressure gauge and dump in my yeast.
(Note- sometimes I will add yeast, then aerate, Again- many discussions to be had. )
#5- I will then purge again with c02 once.
#6- I will attache a blow-off tube and let the fermentation begin! Technically, there is a bit Oxygen in the head-space. I once decided to wait 12 hours for fermentation to start before adding the blow-off tube (so I could purge with c02 and ensure no oxygen). The problem with this is... I barely made it in time to add a blow-off tube. It is just not worth it to me.

Sorry, this is rambling. May I suggest you read some on this thread- it is about the Spike CF series, but a lot of handy info!

https://www.homebrewtalk.com/threads/spike-conical-observations-and-best-practices.645440/

Why bother purging with CO2 at the prior to fermentation at all? The volume of CO2 produced from fermentation is very large in comparison to fermenter volume at the homebrew scale and you should almost be guaranteed to be left with a 100% CO2 headspace after fermentation is complete.

 

[Vale71]

Coolships definately blow the geometry of fermenters out of the water and they work.

For cooling the hot wort to close to pitching temp? Yes, definitely, as that's what they're designed for. I don't see the point of comparing them to fermentation vessels, which serve a completely different purpose, though....

 

[Merleti]

Vale71 I should have said open fermentation.

 

[Nate R]

Why bother purging with CO2 at the prior to fermentation at all? The volume of CO2 produced from fermentation is very large in comparison to fermenter volume at the homebrew scale and you should almost be guaranteed to be left with a 100% CO2 headspace after fermentation is complete.

Perhpas i did not explain right?
When i move wort into the fermentor, i do not pump. I gravity feed so thier is exposure to oxygen. Then i use a food grade oxygen tank to add oxygen.
Then i expose again to add yeast (or before i oxygenate).
After i seal the fermentor up, i have a headspace of non-pure atmospheric air. I want this gone, so i purge.
Just me i guess.

 

[Jtvann]

I'm confused. Oxygen is good for yeast in initial phases ... which is why we Oxygenate. Am I missing the point of purging headspace with CO2 after purposefully adding O2?

 

[NSMikeD]

I'm confused. Oxygen is good for yeast in initial phases ... which is why we Oxygenate. Am I missing the point of purging headspace with CO2 after purposefully adding O2?

IMO, no. The yeast needs O2. IMO, the yeast will purge with CO2 for you, so long as you see the airlock bubble during the initial stage. I do get why you would use O2 instead of air that may contain unwanted bad guys, but my understanding the with active initial fermentation, it's not an issue, the yeast will outcompete the bad guys in that air.

The OP asked about an oversized fermentor. In theory the additional airspace could be an issue if the initial fermentation doesn't purge the air. IMO, making. fermentation bucket is easy and cheap, so I think it shouldn't preclude anyone from adding a smaller fermentor if one expects to brew small batches.

 

[Jtvann]

IMO, no. The yeast needs O2. IMO, the yeast will purge with CO2 for you, so long as you see the airlock bubble during the initial stage. I do get why you would use O2 instead of air that may contain unwanted bad guys, but my understanding the with active initial fermentation, it's not an issue, the yeast will outcompete the bad guys in that air.

The OP asked about an oversized fermentor. In theory the additional airspace could be an issue if the initial fermentation doesn't purge the air. IMO, making. fermentation bucket is easy and cheap, so I think it shouldn't preclude anyone from adding a smaller fermentor if one expects to brew small batches.

Yeah, kinda figured the same. I mean I wouldn't ferment a 5 gallon batch in a barrel fermenter, but anything within reason ought to be fine.

 

[Nate R]

I'm confused. Oxygen is good for yeast in initial phases ... which is why we Oxygenate. Am I missing the point of purging headspace with CO2 after purposefully adding O2?

For me, having a sealed and easy to use fermentor (spike cf5) it only adds an extra 30 seconds or so to purge.
Agree it probably is not needed (how many thousands of years has beer been made in open vats, still today?!).
But, i follow a "minmize any risk i can rule". Aka, if i can easily purge the head space with c02, for a penny or two and 20 seconds of my time, that is an easy step to help reduce a potential, albeit miniscule, infection point.
To each his or her own. That's the great thing about this hobby!

 

[wsmith1625]

I've heard of guys pushing 5 gallons of sanitizer through 2 corny kegs with fermenter co2. That's a lot of co2 from a 5 gallon batch. Makes me feel like you'll be fairly safe doing a smaller batch in a large fermenter. Just my 2 cents.

 

[Jtvann]

For me, having a sealed and easy to use fermentor (spike cf5) it only adds an extra 30 seconds or so to purge.
Agree it probably is not needed (how many thousands of years has beer been made in open vats, still today?!).
But, i follow a "minmize any risk i can rule". Aka, if i can easily purge the head space with c02, for a penny or two and 20 seconds of my time, that is an easy step to help reduce a potential, albeit miniscule, infection point.
To each his or her own. That's the great thing about this hobby!

I dont mind you purging headspace. You do you bud.

I was just asking about "minimize any risk I can" ... what is being minimized? I cant figure out what the point of doing it is, even on a minuscule stage.

 

[Gregory T]

remember the days of vigorously shaking and stirring the wort to aerate it prior to pitching. I aerate by using a venturi in the hose from the kettle to the fermentor

 

[Merleti]

I've made many a venturi but never ended up trying one to aerate wort. I used to use an air pump with a inline filter.

 

[Gregory T]

I've made many a venturi but never ended up trying one to aerate wort. I used to use an air pump with a inline filter.

Here it is

 

[VikeMan]

Aka, if i can easily purge the head space with c02, for a penny or two and 20 seconds of my time, that is an easy step to help reduce a potential, albeit miniscule, infection point.

When you knock all (actually most) of the O2 out of the head space by purging, some of the dissolved O2 will replace it, as it seeks equilibrium between the wort and the headspace.