Your experience with PET Pressure Fermenters - Open Discussion - feedback invited

[CEO Keg King]

With PET Fermenters finding homes in many a brewer's den it would be great to get feedback about our Unitanks etc. DELETED CONTENT WAS HERE Primarily we are interested in PET tanks that work under pressure. Its easy to make a PET vessel that does not need to hold pressure. Much harder to get one to go to 5 bar or more but not impossible. Keep in mind that with PRVs which release at 35 psi that this is the pressure that most car tires operate at so there is a lot of energy. To contain this safely the design and production of the tank requires not only the right machinery but also an expert understanding of the materials and processes.

So please let us know your experiences here and help us do better. Our team is very proud of the high quality tanks that we make right here in Australia and sell all over the world but its always possible for a problem to occur. If problems do happen we are very keen to quickly analyse what happened and use this to improve.

Over to you and please tell us your wishes if you are thinking to get one or about your usage experience if you already have one. Would love to see pictures.

 

[MickDundee]

I bought a Gen 1 Fermentasaurus just over 18 months ago but never pressure fermented in it until now (I upgraded to kegs in July so went out and bought the pressure kit).

I’ve not seen the final results, but I’ve gone from “My Fermentasaurus is only any good for lagers” to “this is amazing” in the space of a week.

This photo was taken 24hrs in, I now have my spunding set happily at 10PSI:

 

[CEO Keg King]

Great looking brew. You know of course that all our range now comes with pressure fittings included. We just felt that it was more costly to mess around with different bits than it was just to do the job right from the word go. You might want to think about upgrading it with a gen 3 kit to get the extra benefits of that.

 

[MickDundee]

Great looking brew. You know of course that all our range now comes with pressure fittings included. We just felt that it was more costly to mess around with different bits than it was just to do the job right from the word go. You might want to think about upgrading it with a gen 3 kit to get the extra benefits of that.

I’m considering upgrading at Christmas time, I should have stopped spending money on my kegerator by then.

I’ve been considering a snubnose, competitor’s products which I dare not name, or a chubby (assuming the Chubby units are here in time for either Christmas present or for spending Christmas money on) as alternatives to the Gen 3.

Not sure I’d go down the collection bottle route next time though - it’s just one more place to worry about leakage. I only ever use the collection bottle when I make lagers to allow me to lager in primary anyway, and I believe the snub nose will allow that because of its shape minimising contact with the trub. I think that’s probably the main benefit over the Chubby if I go down the single piece moulded route.

 

[CEO Keg King]

I’m considering upgrading at Christmas time, I should have stopped spending money on my kegerator by then.

I’ve been considering a snubnose, competitor’s products which I dare not name, or a chubby (assuming the Chubby units are here in time for either Christmas present or for spending Christmas money on) as well as the Gen 3.

Not sure I’d go down the collection bottle route next time though - it’s just one more place to worry about leakage. I only ever use the collection bottle when I make lagers to allow me to lager in primary anyway, and I believe the snub nose will allow that anyway because of its shape. I think that’s probably the main benefit over the Chubby and the all rounder if I go down the single piece moulded route.

Well we are just making Chubbies now and so far the feedback is pretty good on them. The destructive burst tests are coming in at 8 bar so they are definitely good for pressure fermenting. You would have no problem force carbonating in them which is definitely not something I would recommend you trying with the one you did not mention. The pics below are what happened at 20 psi and the lid hit the brewer in the face. He sent the unit to me for analysis. We were shocked by what we saw.

The worst scenario is where the failure occurs underneath the neck because then the whole neck including the lid and neck ring can fly off and that could do some serious damage. A few weeks ago a user sent us such a vessel (not one of ours) that he says had 20 psi for transfer when the thing gave way.

What you can see is a lot of large longitudinal cracks and if you look closely in between evidence of numerous small cracks. This is exactly what we do not want to see. If you purchase a new tank then apart from some maybe very tiny stretch marks there should no stress Cracks. If you can see any then do not pressurise it. What happens is that during each pressurisation the whole tank expands and then contracts. If the manufacturing has not been to the right standard then it does not take long for these cracks to grow and render the vessel unsafe.

So one of the reasons I started this thread was the need to show end users that correctly made PET pressure tanks are great for brewers. EDITED

 

[Neil Whittaker]

I joined the home brew club last year and bought a Fermzilla gen 1 as part of my initial setup. Thus, i've only ever brewed under pressure. My up's and downs are:

Downs:
1. The seal around the lid leaked and in the end I ordered some larger o-rings from china to fix it.
2. If you do a massive dry hope from the collection jar, the hopes swell and still get stuck.
3. Using the supplied tool for opening and dismantling is ok for the top lid, but you need a second tool to make taking the bottom collection jar assembly easier.
4. The overall height means you need a full height.
5. I'd like a half keg version. :-)

Up's
1. No oxygen gets to my beer. Flush the keg with the C02 from the fermentation.
2. Has pushed me to use the features of the product. E.g yeast harvesting, making NEIPA's etc...
3. I can see the fermentation and resolve issues fast.
4. I think for the cost, it is great value.

Would I do things different?
No. The femzilla Gen 1 was the only real option at the time. I do look forward to trying other PET systems in the future though.

 

[CEO Keg King]

I joined the home brew club last year and bought a Fermzilla gen 1 as part of my initial setup. Thus, i've only ever brewed under pressure. My up's and downs are:

Downs:
1. The seal around the lid leaked and in the end I ordered some larger o-rings from china to fix it.
2. If you do a massive dry hope from the collection jar, the hopes swell and still get stuck.
3. Using the supplied tool for opening and dismantling is ok for the top lid, but you need a second tool to make taking the bottom collection jar assembly easier.
4. The overall height means you need a full height.
5. I'd like a half keg version. :-)

Up's
1. No oxygen gets to my beer. Flush the keg with the C02 from the fermentation.
2. Has pushed me to use the features of the product. E.g yeast harvesting, making NEIPA's etc...
3. I can see the fermentation and resolve issues fast.
4. I think for the cost, it is great value.

Would I do things different?
No. The femzilla Gen 1 was the only real option at the time. I do look forward to trying other PET systems in the future though.

You might want to check around the neck of your unit to see if it looks like the pic. If so be very careful with pressure. You might also consider the better lid with all the new features (Next pictures). Means you can have a Thermowell, dry hop port,float ball stays in the centre and you can attach a spray ball straight on the thread on the inside of the lid.

 

[Neil Whittaker]

Yep, coming up to one year old.

Love all the features of the new lid, would love those. :-)
I sent a quick email to the uk supplier. See if they think it's ok to use under pressure since its never been over 12 psi.

 

[AdeDunn]

Ok, well I have a gen 1 Fermentasaurus.

At first, I was on the fence with it, I found it a bit of a pain in the rear to use to be honest, and fiddly to assemble... However, it's like many things though, it was just a learning curve. Full disclosure though, I don't ferment under pressure, I use an airlock.

The cons with it: No matter how full the collection bottle is when I put it back on, there is still a gap between the top of it and the butterfly valve, so you get a bubble. This is a gen 1 though, and you guys are making the Gen 3 now, which doesn't even have a butterfly valve... lol

My process now is, I fill it up, pitch the yeast, leave it only long enough for the trub to properly settle out, then whilst the yeast is very very active, I close the valve, remove the bottle, dump the trub, replace the bottle and open the valve. Air bubbles into the wort, but it's still actively fermenting is what I figure. You'd have to worry more if you were using it to collect yeast, but I'm not. I only dump the yeast when it comes time to bottle.

The whole collection bottle thing makes bottling super easy, no need to transfer to a bottling bucket. I just add the sugar solution after removing the bottle with the yeast in it. Put the supplied barb on the bottom, attach hose (filter if needed) and bottler, and bingo, good to go.

The jacket I bought with it has been a real boon too. It's not only allowed me to block out light, but also to have some sort of temperature control. In a room with an ambient of about 18 degrees C, using freezer packs, a digital thermometer probe read between 13-14 degrees C, and when placed against the side of the fermenter it's stayed at a steady 14-15 degrees C using the freezer packs (digital thermometers of this type or infamously unreliable by a degree or so, hence using it as a rough guide only).

It could be my imagination as well, but I swear I've been getting better attenuation in it, using the same yeast etc. Possibly thanks to the conical design? Very slight though, and so many factors when it comes to apparent attenuation that it could be just coincidence.



I have no regrets. It's made bottling day easier, and the jacket is really a nice little addon for me. I would say they're worth it even if you aren't going for pressure.

 

[MickDundee]

Ok, well I have a gen 1 Fermentasaurus.

At first, I was on the fence with it, I found it a bit of a pain in the rear to use to be honest, and fiddly to assemble... However, it's like many things though, it was just a learning curve. Full disclosure though, I don't ferment under pressure, I use an airlock.

The cons with it: No matter how full the collection bottle is when I put it back on, there is still a gap between the top of it and the butterfly valve, so you get a bubble. This is a gen 1 though, and you guys are making the Gen 3 now, which doesn't even have a butterfly valve... lol

My process now is, I fill it up, pitch the yeast, leave it only long enough for the trub to properly settle out, then whilst the yeast is very very active, I close the valve, remove the bottle, dump the trub, replace the bottle and open the valve. Air bubbles into the wort, but it's still actively fermenting is what I figure. You'd have to worry more if you were using it to collect yeast, but I'm not. I only dump the yeast when it comes time to bottle.

The whole collection bottle thing makes bottling super easy, no need to transfer to a bottling bucket. I just add the sugar solution after removing the bottle with the yeast in it. Put the supplied barb on the bottom, attach hose (filter if needed) and bottler, and bingo, good to go.

The jacket I bought with it has been a real boon too. It's not only allowed me to block out light, but also to have some sort of temperature control. In a room with an ambient of about 18 degrees C, using freezer packs, a digital thermometer probe read between 13-14 degrees C, and when placed against the side of the fermenter it's stayed at a steady 14-15 degrees C using the freezer packs (digital thermometers of this type or infamously unreliable by a degree or so, hence using it as a rough guide only).

It could be my imagination as well, but I swear I've been getting better attenuation in it, using the same yeast etc. Possibly thanks to the conical design? Very slight though, and so many factors when it comes to apparent attenuation that it could be just coincidence.

View attachment 31988View attachment 31987View attachment 31986
View attachment 31985View attachment 31984
I have no regrets. It's made bottling day easier, and the jacket is really a nice little addon for me. I would say they're worth it even if you aren't going for pressure.

I badly oxidised a batch that I brewed for my mate’s stag do when I got mine by misjudging the timings of emptying the collection bottle - I ended up buying a higher capacity Sodastream bottle (they have the same threads) and then I didn’t need to empty the bottle during fermentation.

 

[CEO Keg King]

Yep, coming up to one year old.
View attachment 31983

Love all the features of the new lid, would love those. :-)
I sent a quick email to the uk supplier. See if they think it's ok to use under pressure since its never been over 12 psi.

Don’t use it under pressure mate. Just use the bubbler.

 

[CEO Keg King]

Ok, well I have a gen 1 Fermentasaurus.

At first, I was on the fence with it, I found it a bit of a pain in the rear to use to be honest, and fiddly to assemble... However, it's like many things though, it was just a learning curve. Full disclosure though, I don't ferment under pressure, I use an airlock.

The cons with it: No matter how full the collection bottle is when I put it back on, there is still a gap between the top of it and the butterfly valve, so you get a bubble. This is a gen 1 though, and you guys are making the Gen 3 now, which doesn't even have a butterfly valve... lol

My process now is, I fill it up, pitch the yeast, leave it only long enough for the trub to properly settle out, then whilst the yeast is very very active, I close the valve, remove the bottle, dump the trub, replace the bottle and open the valve. Air bubbles into the wort, but it's still actively fermenting is what I figure. You'd have to worry more if you were using it to collect yeast, but I'm not. I only dump the yeast when it comes time to bottle.

The whole collection bottle thing makes bottling super easy, no need to transfer to a bottling bucket. I just add the sugar solution after removing the bottle with the yeast in it. Put the supplied barb on the bottom, attach hose (filter if needed) and bottler, and bingo, good to go.

The jacket I bought with it has been a real boon too. It's not only allowed me to block out light, but also to have some sort of temperature control. In a room with an ambient of about 18 degrees C, using freezer packs, a digital thermometer probe read between 13-14 degrees C, and when placed against the side of the fermenter it's stayed at a steady 14-15 degrees C using the freezer packs (digital thermometers of this type or infamously unreliable by a degree or so, hence using it as a rough guide only).

It could be my imagination as well, but I swear I've been getting better attenuation in it, using the same yeast etc. Possibly thanks to the conical design? Very slight though, and so many factors when it comes to apparent attenuation that it could be just coincidence.

View attachment 31988View attachment 31987View attachment 31986
View attachment 31985View attachment 31984
I have no regrets. It's made bottling day easier, and the jacket is really a nice little addon for me. I would say they're worth it even if you aren't going for pressure.

Well take a look at the gen 3 upgrade maybe.

 

[CEO Keg King]

Well what an interesting evening I had yesterday. It seems my efforts to try and undo the confusion in end user's minds about PET tanks and their different qualities was very useful to quite a number of you who contacted me subsequently. My reason for opening up this sort of discussion is that a lot of people are thinking Fermentasaurus but then confusing it to the point that similar looking products are equivalent or even from the same source. So our efforts are concentrated on what kind of burst pressure our PET vessels achieve, how they are protected and how best to use them. Working with pressure in Fermentation is not really all that hard if one follows some basic rules and it definitely helps brewers to make better beers. It is also important that people are aware that "FERMENTASAURUS" is a registered and protected trademark which belongs to Keg King. Our tank products are made on highly specialised equipment which allows large size tanks to be made in one operation rather than the two stage processes involving the reheating of formed PET vessels to then blow them into larger vessels. Reheating PET has a serious disadvantage in that it reduces the strength of the end product because it messes with the chain structure of the polymer. So happy to answer any of your questions and help you get more from your favourite pastime. If it gets real technical then I will get help from our team so bear with me.

 

[Neil Whittaker]

Well as you can see above, I posted a picture of my FermZilla with the stress marks. I sent that picture to the company I purchased it from (BKT) to ask if it was still ok to use. The response was.

Hi Neil,
I'll get a replacement tank out to you and a replacement thicker lid seal tomorrow.
Super happy to support any of our other customers in this way - by all means ask anyone else with similar marks to get in touch and we'll sort them out also.
Give me a shout if you need anything else.
Cheers, Jonny

I tip my hat to their customer service and attitude, well done.

 

[CEO Keg King]

Well as you can see above, I posted a picture of my FermZilla with the stress marks. I sent that picture to the company I purchased it from (BKT) to ask if it was still ok to use. The response was.

Hi Neil,
I'll get a replacement tank out to you and a replacement thicker lid seal tomorrow.
Super happy to support any of our other customers in this way - by all means ask anyone else with similar marks to get in touch and we'll sort them out also.
Give me a shout if you need anything else.
Cheers, Jonny

I tip my hat to their customer service and attitude, well done.

Which is exactly what they should do. Just make sure the replacement does not have similar cracks. You might want to ask about what burst pressure they test these units to also.

 

[uDicko]

Jonny @BrewKegTap is a legend

 

[foxy]

Well as you can see above, I posted a picture of my FermZilla with the stress marks. I sent that picture to the company I purchased it from (BKT) to ask if it was still ok to use. The response was.

Hi Neil,
I'll get a replacement tank out to you and a replacement thicker lid seal tomorrow.
Super happy to support any of our other customers in this way - by all means ask anyone else with similar marks to get in touch and we'll sort them out also.
Give me a shout if you need anything else.
Cheers, Jonny

I tip my hat to their customer service and attitude, well done.

It just goes to show that it is important to inspect your vessel before use, well spotted Neil and good on the supplier for replacing the faulty vessel.

 

[CEO Keg King]

Just to show how strong our PET vessels are we decided to do a test today to see if we can use them like a gas cushion to lift our pickup truck. Now the truck weighs over 2 tons and we went for the front right wheel so to have max engine weight on there. By sliding the cursor back and forth you can see how the vessels inflates and deflates.

Please do not try this yourself - we donned safety gear and put the 60 litre snubnose inside two strong plastic back just in case. Meant we just had to have the camera in place and so only one angle shown. Have a few shots here though so you can see the setup. We did the same wiTh a 35 litre.



I

 

[Doive]

I have a Gen 2 Fermentasaurus, affectionately nicknamed 'Rexie' by my wife. I've been using it since May for pressure fermenting, usually between 10 and 15psi, then doing oxygen-free transfer into my corny kegs or into a secondary for fruit additions, etc. The conical design has been a great help in leaving the trub and yeast behind, while getting the maximum beer out. I use it with an ispindel for checking the progress of the fermentation, and it's really changed how I brew, and I would say also the quality of the beers produced.

 

[AdeDunn]

I won't be using Lallemand Voss in mine ever again I know that!! Stuff sticks to the PET like super glue, especially at krausen height. Took soaking in PBW then VWP to get it all off, and was still difficult as you can't get your arm in there to give it a good rub. So note to self, avoid yeasts that like to stick to the PET too much, as it makes cleaning afterwards a right PITA... Use my Speidel for those, with it's wide neck and anti stick plastic... lol