Using Kegland spunding valve for pressure fermentation

[Dilettante Brewing]

Hello, couple of questions about this that I don’t see answered definitively elsewhere (apologies if I’m missing them).

1. When using the spunding valve does anyone connect the outlet side after the bow tie valve to a blow-off tube immersed in sanitiser? Is this necessary as it would be if no valve were fitted?

2. Do people dial in the valve to the required pressure (eg 10 psi) right from the start of fermentation or run it initially with zero pressure dialled in and then ramp it up?

3. What temperature do people start fermentation at? Normal fermentation temperature for the yeast (eg 10C-15C for a lager yeast) or a higher temperature suitable for pressure fermentation (eg 20C-25C). Does it make a difference to the results?

Thanks

 

[foxy]

Hello, couple of questions about this that I don’t see answered definitively elsewhere (apologies if I’m missing them).

1. When using the spunding valve does anyone connect the outlet side after the bow tie valve to a blow-off tube immersed in sanitiser? Is this necessary as it would be if no valve were fitted?

2. Do people dial in the valve to the required pressure (eg 10 psi) right from the start of fermentation or run it initially with zero pressure dialled in and then ramp it up?

3. What temperature do people start fermentation at? Normal fermentation temperature for the yeast (eg 10C-15C for a lager yeast) or a higher temperature suitable for pressure fermentation (eg 20C-25C). Does it make a difference to the results?

Thanks

1. You need to immerse a blow-off tube into sanitiser otherwise bacteria will be getting into your fermenter. And change the sanitiser regularly, maybe something to do with CO2 going through and breaking it down.
2. Let the yeast have a couple of days fermenting without any pressure before applying pressure.
https://www.terifahrendorf.com/Closed-Pressurized-Fermenatation.pdf
3.Always remember yeast is capable of raising the temperature above ambient due to the exothermic energy produced. What I do is start low 16-17C ambient for ale. If you are using a thermowell or taping a probe on the side of the fermenter then start at about 20C

 

[Sadfield]

1) No, it's a one way valve. The positive pressure keeps anything out.

2) After the lag phase of yeast, typically 12 hrs.

3) It depends on what you are brewing.

 

[RichardM]

1) No, it's a one way valve. The positive pressure keeps anything out.

2) After the lag phase of yeast, typically 12 hrs.

3) It depends on what you are brewing.

I agree with this.

 

[Dilettante Brewing]

Thanks all - very helpful.

 

[carl_saint]

I agree with this.

Seconded!

 

[foxy]

Seems a bit more discussion is needed, pitched yeast has a lag phase of 24 to 36 hours. So there is no top pressure to keep any spoiling bacteria out of the wort. This is why it is recommended to attach a blow-off hose into sanitiser.
During the first couple of days of fermentation, the CO2 is stripping H2S something you don't want in the finished beer hence the reason for letting the unrestricted expelling of CO2 before applying any pressure.
https://www.kegland.com.au/blogs/ke...ses, you will,You are now pressure fermenting!

 

[Sadfield]

Seems a bit more discussion is needed, pitched yeast has a lag phase of 24 to 36 hours.

OK. Personally, I find Dr. Chris White's estimate of 3-15 is more realistic. And, seeing co2 coming out of solution may take longer. If you are using pressure to reduce esters, then you don't want to wait until esters are produced during exponential growth, to start adding pressure.

https://byo.com/article/fermentation-time-line/
.

So there is no top pressure to keep any spoiling bacteria out of the wort.

It's a closed system until there's positive pressure to over come the spring pressure behind the valve, that's the primary function of a valve, they open when required.

You know pressure fermenting reduces H2S, you've used the counter argument before that Chris White prefers lagers that haven't been overly pressure fermented and contain some Sulphur in the flavour profile. He's says as much in the above video at 30 minutes. He's even told you in person.

Sadfiefld, I spoke to Chris White when he visited Melbourne, you have to read between the lines, he is in the business of making money and money he makes from the gullible. one on one he prefers no top pressure but says that you can put all lager yeast under some pressure not just WLP 925 as long as it is around 10PSI and below 20C.

 

[Herms bay]

I have brewed many (50+) lagers under pressure in this way, I have never put the output from the spunding valve in sanitiser and never had a problem. The pressure is driving CO2 out so nothing can go in.
I have pressurised the fermenter and then set the spunding valve to the correct pressure and sometimes just let it do its own thing if I am sure the valve is set right, and again had no problems. I mainly use SafLager 34/70 yeast and maybe it's very tolerant. I have also put into the fermenter at 22degC and it has raised the temp to 24-25 with no real adverse effects.
I can't vouch for any other yeasts with this method.
I also just tip the yeast (2 packets in 55 litres) in the wort when pitching from my counter chiller and it's going crazy in 24 hours.

 

[RoomWithABrew]

Turn the tap on the spunding valve clockwise to ensure it is set to a pressure above 0 psi, then put it on your fermenter gas post.
As the pressure rises you will see the gauge increase it's reading when at your desired pressure turn the tap anti clockwise until it vents and then turn a little clockwise to stop the gas loss. Recheck and adjust as necessary.

There is no need to run a blow off tube unless you have the spunding valve fully open but if you are open fermenting you don't need the spunding valve on just leave the lid off and cover to protect from invasion by flying insects. Fruit flies love hoppy beers.

 

[Sadfield]

Actually, I think the whole reason for yeast creating esters is to attract fruit flies, they're free transport. So, less of a risk with pressure fermenting.


Interestingly, if you Google image search this, the primary reason the originator (a New Hampshire homebrewer) does it, is for the same visual feedback people like from bubbling air locks.

 

[Agentgonzo]

I see no reason why you would want/need to put the output into sanitiser.
The point of an airlock/blow-off tube in sanitiser is to prevent air (and contaminants) getting back into your fermenter from the environment.

The spunding valve is a one-way valve, ie, stuff can only flow 'outwards'. So the spunding valve is preventing air/contaminants from getting back into your fermenter anyway so there's no need to have both.

 

[fluketamer]

I was going to say you will get a lot of different answers as evidenced by the posts above. I found too many options when researching. I decided to go with blow off tube first out of fear of blocking a Prv with kreusen. Then at 24 hours I capped it with a spundy set to 12 psi. I am not disappointed wit the result. But I don’t think the blow off is needed and I have seen more than one poster say just cap it from the start.

Spoiler alert no matter what you do u will make beer .

 

[Herms bay]

In the company I work for, the safety assessor in a HAZOP would say " what if the valve broke and it just went open". We would say it wouldn't as back pressure forces it shut. He would then insist on sanitizer on the output.
There is no harm I suppose in doing that but it just seems redundant.
Looks sexier than this boring set up as well!

 

[hoppyscotty]

I've always assumed the blow tie is closed until pressure builds to the set level. If you're really paranoid then you could fully close it until pressure built before opening, but this would require manual monitoring.

But being paranoid is not a bad thing in this game so if you really wanted to be belt and braces about it then no harm in venting through sanitiser.

The more commercial design uses a tapered plug pre-loaded with a spring, but still vent the gas through a bowl of sanitiser so there is clearly a view on the commercial scene that it should be vented through sanitiser.

Personally when I've used a blow tie before I've not bothered but I wouldn't necessarily say that is best practice. just use my bowtie for venting kegs during pressure transfers now.

 

[Dilettante Brewing]

Thanks again everyone - really useful discussion that I’ve not seen covering all these points in one place before. My takeaways against my 3 original questions are:

1. Don’t need a blow-off tube attached to the spunding valve unless the valve is fully open with no positive pressure from the fermenter side. But it doesn’t hurt to attach one as a ‘belt & braces’ approach.

2. Depending on your view of the length of the yeast’s lag phase, you can probably set the spunding valve to create pressure right from the start of fermentation.

3. Aim to start fermentation at the normal operating temperature for the yeast but if it’s a bit higher that should be OK.

 

[hoppyscotty]

To point 3 I've spoken with alot of brewers at various festivals etc and most dont seem to use pressure fermenting as such and will only close up the fermenter in the latter stages of fermentation to ensure they get the flavour esters from the years I the early part of (non pressure) fermentation, and to start the process of natural carbonation.

When I've pressure fermented in the past (not saying I've done it correctly or in accordance with best practice) I've just set the spunding valve and let the pressure build...usually the scale on the spunding valve is not particularly accurate so once upto pressure and the valve is blowing I'll adjust to the correct target pressure.

The thing I get my knickers in a twist ab0ut with pressure fermenting is what should be the corresponding temperature for any given pressure. There seems to be no calculator or guidance to tell you for this yeast and this pressure your optimal temperature is x.

 

[Herms bay]

I only ever pressure ferment with lagers that don't want any ester type component.
I don't know if i'm making this up from a dream..I'm at that age! but I thought lagers were bottom yeasts and in commercial lager they are in 10m fermentation silos so they effectively see 1 bar (14psi) pressure.
That may be complete tosh as I probably got it from youtube or a forum..

 

[Agentgonzo]

but I thought lagers were bottom yeasts and in commercial lager they are in 10m fermentation silos so they effectively see 1 bar (14psi) pressure.

Partly true.
"Bottom fermenter" and "top fermenter" doesn't mean that yeast only ferments at the bottom/top. In reality, the yeast is in suspension throughout the wort and ferments at all points in the wort.

But you are correct in that at the bottom of a 10m fermentation vessel, there is an additional 1 atm (14-15PSI) of pressure

 

[Sadfield]

There seems to be no calculator or guidance to tell you for this yeast and this pressure your optimal temperature is x.

How can there be? Pressure is just a mechanism for suppressing esters and everyone has differing expectations.

Commercial breweries rarely pressure ferment because they want esters, they are a unique fingerprint of how their brewery and process shapes the taste and aroma of their beers. The general public either like it or they don't.

Homebrewers on the other hand brew for just one palate and expectation. Even if we all pressure ferment and log results somewhere, the results would be so varied. Someone who's route to homebrewing was drinking Miller Light in Milwaukee will judge esters differently to someone drink Marstons in Matlock. Throw into the equation workarounds for the fermenting environment, such as ambient temperature, what would optimal be?