About how fast does spunding go?

[iandanielursino]

I've seen my equipment (Spike CF10 with PRV) get 12 PSI when it was working properly one time overnight, but that was on the first day of fermentation (I'm in the middle of some troubleshooting with technical support but that's a topic for elsewhere). So this time, on the third afternoon (fourth day after starting fermentation in the evening so about 3.5 days) I started spunding a 5 gallon batch of APA with OG of 1.047, and I should add that the fermentation was slow for the first 24 hours.

In a couple hours I got up to 2.5 PSI, then the next morning it was up to 4 PSI. Is that a normal spund rate for this far into fermentation or is it rather slow?

I'm curious about how fast people usually get up to pressure when spunding, particularly when they have not been doing it the entire fermentation.

 

[McMullan]

Have you taken a gravity reading?

 

[iandanielursino]

Oh right that makes sense, I can tell how far along it is by the gravity. I'll go out to the brewery and take a reading this afternoon. Also the temp is 68 (in a freezer fermentation chamber) if that matters.

 

[DonT]

I've seen my equipment (Spike CF10 with PRV) get 12 PSI when it was working properly one time overnight, but that was on the first day of fermentation (I'm in the middle of some troubleshooting with technical support but that's a topic for elsewhere). So this time, on the third afternoon (fourth day after starting fermentation in the evening so about 3.5 days) I started spunding a 5 gallon batch of APA with OG of 1.047, and I should add that the fermentation was slow for the first 24 hours.

In a couple hours I got up to 2.5 PSI, then the next morning it was up to 4 PSI. Is that a normal spund rate for this far into fermentation or is it rather slow?

I'm curious about how fast people usually get up to pressure when spunding, particularly when they have not been doing it the entire fermentation.

I've never really tracked the rate of pressure increase, but I've seen 15psi after an overnight stay. Your's does appear to be a bit slow. What yeast did you use?

 

[iandanielursino]

I've never really tracked the rate of pressure increase, but I've seen 15psi after an overnight stay. Your's does appear to be a bit slow. What yeast did you use?

I think Wyeast 1318 London Ale III Yeast, it's the kind where it comes double bagged and you're supposed to pop the inner one to let it get a yeast starter inside of the bag.

I forgot to pop it first so I imagine that's why it was real slow for the first day. The reason why spunding didn't start until the fourth day is because I had a pressure leak, and I still may. I popped the top, observing as I did a large krausen, and re-buttoned it tighter. Ultimately this will be decided based on whether the pressure starts going back down, I mostly made this thread out of curiosity since I have no ballpark understanding of spunding speed so I don't want to derail it too much into my case.

 

[DonT]

I think Wyeast 1318 London Ale III Yeast, it's the kind where it comes double bagged and you're supposed to pop the inner one to let it get a yeast starter inside of the bag.

I forgot to pop it first

That's likely the reason it started slow. Did you do a starter?

The reason why spunding didn't start until the fourth day...

I usually don't start the spund until there is about 10 points left as I use the fermentation to push star-san out of a keg. I have a Spike Flex+

 

[iandanielursino]

Never mind the gravity, it started backsliding from 4 PSI to 3 PSI. Oh well.

So, to the subject of the thread, it sounds like your pressure should usually raise double digits over-night unless you started very late in fermentation.

 

[sbro]

Sounds like a slow leak somewhere. Spray some bubble liquid on things to find it. Star San doesn’t work well to find small leaks in my experience.

 

[iandanielursino]

I was discussing it already in De-carbonating for bottle conditioning, I'm pretty sure it has to be the lid not the PRV or any of the fittings as the tank functions at 12 PSI and holds the same gauge pressure for over 2 weeks, it just doesn't function at low pressures.

 

[sbro]

I have a cf5 that I put the all in one prv on and it held 12 psi fine for about 5 days after starting a cider then it slowly dropped to near zero. Starsan revealed no leaks, but later I used bubble mix which revealed a small leak on one of the prv fittings that I retaped and had to torque pretty good before it sealed.

 

[DuncB]

started spunding twelve hours ago in fermentasaurus.
now at 8 psi and one point of gravity drop , ispindel trace is flat. It's a kveik ferment and i was a bit late getting the spund valve on.
You must have a leak, I had a leak in the metal spund valve pipes , could keep pressure during active ferment but not once ferment slowed. It was tricky to find.

 

[McMullan]

Big openings on FVs can be a challenge to work with. Best advice, once this fermentation is finished and transferred, is fill the FV with water and practice getting a reliable seal.

 

[doug293cz]

Rate of spunding pressure build up is proportional to the rate of fermentation - rate of CO2 generation is proportional to the rate of fermentation. The fermentation rate can be determined from the derivative of the SG curve from a Tilt, Ispindle, Rapt Pill, etc. You shouldn't try to take the derivative of the raw data, as it is very noisy, and the derivative of noisy data is even more noisy than the raw data. Therefore you should do some kind of piecewise spline fit to the data, and take the derivative of the fitted curve.

In general, the rate of fermentation curve should look something like this:

Lag time is usually hours to a few 10's of hours, and active fermentation time is typically two to ten days, depending on yeast strain, pitch rate, temperature, OG, O2 content of wort, phase of the moon, whether you are on the cusp of Sagittarius or not, etc. Yeast will do what they want to do at their own rate.

If you start spunding at peak fermentation rate, pressure will build rapidly, on the other hand if you start after fermentation has slowed down, then pressure will build more slowly.

Brew on

 

[DuncB]

Thank you nice graph @doug293cz
Spunding 24 hours in at 10 psi.
Very much started at tail end of ferment 1 day 12hr on my graph. Ferment pretty much finished and beer clearing, might get a couple more psi over the next few days. We'll see.

 

[iandanielursino]

I have a cf5 that I put the all in one prv on and it held 12 psi fine for about 5 days after starting a cider then it slowly dropped to near zero. Starsan revealed no leaks, but later I used bubble mix which revealed a small leak on one of the prv fittings that I retaped and had to torque pretty good before it sealed.

Yeah I went through something similar, now I can hold pressure for over 2 weeks. So my issue is to do with smaller pressures under 10 or else my lid install is not reliable.

I wish I got the ss brewtech PRV instead since it has no threads, gauge, or gaspost built in.

Big openings on FVs can be a challenge to work with. Best advice, once this fermentation is finished and transferred, is fill the FV with water and practice getting a reliable seal.

If there would be a gas leak at low pressure that means it won't hold water?

 

[McMullan]

If there would be a gas leak at low pressure that means it won't hold water?

Less CO2 waste during testing, if it’s filled with water and it kind of mimics wort. IME, there’s usually a knack, technique, to getting things like this to work and it isn’t always conveyed well in the instructions provided.

 

[iandanielursino]

Less CO2 waste during testing, if it’s filled with water and it kind of mimics wort. IME, there’s usually a knack, technique, to getting things like this to work and it isn’t always conveyed well in the instructions provided.

I actually test with air.

 

[McMullan]

I actually test with air.

If you’ve got a compressor set up with compatible fittings, even better for testing.

 

[doug293cz]

Less CO2 waste during testing, if it’s filled with water and it kind of mimics wort. IME, there’s usually a knack, technique, to getting things like this to work and it isn’t always conveyed well in the instructions provided.

Testing with a vessel water filled and CO2 pressurized in the headspace won't work very well. The water will absorb CO2 (become carbonated), the pressure will drop - even if you don't have any leaks, but you will think you have a leak.

Compressed air is best for testing, without wasting CO2.

Brew on

 

[McMullan]

Testing with a vessel water filled and CO2 pressurized in the headspace won't work very well. The water will absorb CO2 (become carbonated), the pressure will drop - even if you don't have any leaks, but you will think you have a leak.

Compressed air is best for testing, without wasting CO2.

Brew on

True for a slow leak. I’d want to test things more quickly to begin with then set it and check for a slow leak once satisfied. Ideally without water, I guess, even when using air. Don’t most gases go into solution under pressure?

 

[DuncB]

Up to 18 psi now and I've turned off the heating. I'll see what it's reached as it cools to ambient ( around 19C) over the next couple of days.
I'm still waiting for my compressor, but no leaks to test at the moment ( fingers crossed).

 

[mac_1103]

Don’t most gases go into solution under pressure?

Yes but air is 78% nitrogen and nitrogen is ~100x less soluble in water than CO2 at any given pressure.

 

[iandanielursino]

Last few days my tank has stayed around 3 PSI, maybe inching down slightly. Not sure what it would mean if it actually stays at 3, I mean the way the tank is supposed to work it shouldn't have been able to go from 4 PSI to 3 PSI since the temperature remained constantly within a degree or two of 68

 

[DuncB]

My fermenter at 20 psi and 20C now so built to 2.1 vols.

 

[iandanielursino]

So yeah it stayed at 3. Does that mean at this point that there's a leak only at moderate PSI between 4 and some number less than 12? I'm very confused. I'll try some trials with air though at various pressures.

 

[iandanielursino]

Found the issue with a submersion test. And seem to have fixed it by using yellow instead of white tape.

Still I hope spike would be open to sending me a PRV without the holes drilled in it, or refunding so I can buy the Ss BrewTech one, because I am not a fan of NPT anymore.

 

[mac_1103]

a PRV without the holes drilled in it

Aren't the holes where it vents?

 

[iandanielursino]

Aren't the holes where it vents?

I mean the NPT holes where you attach the gauge and the gas post. Those give me no end of trouble. All the other TC PRVs like this on the market like Brew Built and Ss BrewTech don't include a gauge and a gas post in the same unit for that reason.