Ask The Brewmasters

Hi Fancesco,

I don't have experience with that machine specifically, but I do have some experience with a comac 24-4.  The DO numbers suggest that your getting a pretty good purge through the fill and I think your on the right track. 

Our TPO's were stubbornly up in the 125-150 range.  We ended up adjusting our bubble breaker down (physically) and significantly lowering the flowrate of CO2 to "wash over the can".  It helped, but didn't get us where we wanted to be.  We ended up adjusting the snift button decompression lever to get less off gassing post decompression.  We got the best results with a little bit of lace as opposed to the "Black Fill" or no foam at all.  Our typical DO range with this approach was 15-40ppb with TPOs in the 50-75ppb range. 

If your seeing spikes on specific valves...check the snift path for flow restriction.  I've cleaned hops (that somehow snuck through the centrifuge) out of those valves assemblies more times than I care to remember.     

Hey Francesco,

I can't speak to the Comac specifically, but we have found that proper under lid gassing (ULG) set points are one of the main drivers for controlling TPO on our line. For reference we are running a Kosme/Krones 16/4. Our average TPOs are 30-35ppb: shaken cans measured on AP Oxy QC and then calculated via the head space equation. 

For the ULG, we found that a combination of low pressure AND high flow was best. We have settled on ~20psi which is well below the mfr recommended set point of 50-70psi. For flow we are at 320 L/min which is higher than the mfr set point of 275 L/min. Re. flow we did find a significant negative correlation between flowrate and TPO but found it maxed out at 320 and any higher flow was deemed wasteful. We first went down this path based on various MBAA presentations we dug through - one poster (attached) actually references a Comac.

For the bubble breaker we also brought the pressure down as low as possible to break fish eye bubbles - ~4-5psi, which was also well below the set point recommended. We don't have a gas flow meter on the bubble breaker. We ultimately found there was not a linear relationship and it was more qualitative (did it break the bubbles not?), so we just make sure its breaking bubbles without wasting gas. 

All the above said, we have found that good fob formation is still critical for controlling TPO. We can 'see' bad TPO based on foam formation and will adjust filler set points accordingly. Snifting and snifting stabilization are the major parameters we will adjust. Caution, as this can drive up loss. Thus far we have optimized this to keep loss at ~1-1.5% and low TPOs but know we can bring the loss % down at the expense of TPO.

It is worth noting that for the last 3 months we have been running the ULG and bubble breaker with nitrogen, as we've been under a CO2 allocation. We found no change to TPO using nitrogen.

I am interested to see what others suggestions are. We're happy with our numbers but the seamer is a major gas consumer and we'd love to bring our usage down if possible without sacrificing TPO. 

Hi Fancesco,

I don't have experience with that machine specifically, but I do have some experience with a comac 24-4.  The DO numbers suggest that your getting a pretty good purge through the fill and I think your on the right track. 

Our TPO's were stubbornly up in the 125-150 range.  We ended up adjusting our bubble breaker down (physically) and significantly lowering the flowrate of CO2 to "wash over the can".  It helped, but didn't get us where we wanted to be.  We ended up adjusting the snift button decompression lever to get less off gassing post decompression.  We got the best results with a little bit of lace as opposed to the "Black Fill" or no foam at all.  Our typical DO range with this approach was 15-40ppb with TPOs in the 50-75ppb range. 

If your seeing spikes on specific valves...check the snift path for flow restriction.  I've cleaned hops (that somehow snuck through the centrifuge) out of those valves assemblies more times than I care to remember.     

Hey Francesco,

I can't speak to the Comac specifically, but we have found that proper under lid gassing (ULG) set points are one of the main drivers for controlling TPO on our line. For reference we are running a Kosme/Krones 16/4. Our average TPOs are 30-35ppb: shaken cans measured on AP Oxy QC and then calculated via the head space equation. 

For the ULG, we found that a combination of low pressure AND high flow was best. We have settled on ~20psi which is well below the mfr recommended set point of 50-70psi. For flow we are at 320 L/min which is higher than the mfr set point of 275 L/min. Re. flow we did find a significant negative correlation between flowrate and TPO but found it maxed out at 320 and any higher flow was deemed wasteful. We first went down this path based on various MBAA presentations we dug through - one poster (attached) actually references a Comac.

For the bubble breaker we also brought the pressure down as low as possible to break fish eye bubbles - ~4-5psi, which was also well below the set point recommended. We don't have a gas flow meter on the bubble breaker. We ultimately found there was not a linear relationship and it was more qualitative (did it break the bubbles not?), so we just make sure its breaking bubbles without wasting gas. 

All the above said, we have found that good fob formation is still critical for controlling TPO. We can 'see' bad TPO based on foam formation and will adjust filler set points accordingly. Snifting and snifting stabilization are the major parameters we will adjust. Caution, as this can drive up loss. Thus far we have optimized this to keep loss at ~1-1.5% and low TPOs but know we can bring the loss % down at the expense of TPO.

It is worth noting that for the last 3 months we have been running the ULG and bubble breaker with nitrogen, as we've been under a CO2 allocation. We found no change to TPO using nitrogen.

I am interested to see what others suggestions are. We're happy with our numbers but the seamer is a major gas consumer and we'd love to bring our usage down if possible without sacrificing TPO. 

Hi Fancesco,

I don't have experience with that machine specifically, but I do have some experience with a comac 24-4.  The DO numbers suggest that your getting a pretty good purge through the fill and I think your on the right track. 

Our TPO's were stubbornly up in the 125-150 range.  We ended up adjusting our bubble breaker down (physically) and significantly lowering the flowrate of CO2 to "wash over the can".  It helped, but didn't get us where we wanted to be.  We ended up adjusting the snift button decompression lever to get less off gassing post decompression.  We got the best results with a little bit of lace as opposed to the "Black Fill" or no foam at all.  Our typical DO range with this approach was 15-40ppb with TPOs in the 50-75ppb range. 

If your seeing spikes on specific valves...check the snift path for flow restriction.  I've cleaned hops (that somehow snuck through the centrifuge) out of those valves assemblies more times than I care to remember.     

Hi Fancesco,

I don't have experience with that machine specifically, but I do have some experience with a comac 24-4.  The DO numbers suggest that your getting a pretty good purge through the fill and I think your on the right track. 

Our TPO's were stubbornly up in the 125-150 range.  We ended up adjusting our bubble breaker down (physically) and significantly lowering the flowrate of CO2 to "wash over the can".  It helped, but didn't get us where we wanted to be.  We ended up adjusting the snift button decompression lever to get less off gassing post decompression.  We got the best results with a little bit of lace as opposed to the "Black Fill" or no foam at all.  Our typical DO range with this approach was 15-40ppb with TPOs in the 50-75ppb range. 

If your seeing spikes on specific valves...check the snift path for flow restriction.  I've cleaned hops (that somehow snuck through the centrifuge) out of those valves assemblies more times than I care to remember.     

Francesco,

What are your DO at the filler?  Specifically, coming right off the fill valve?  

Hi David,

The DOs at the sample point closest to the filler bowl are around 15ppb, about the same as the BBT. 

Cheers,

Francesco

Hi David,

The DOs at the sample point closest to the filler bowl are around 15ppb, about the same as the BBT. 

Cheers,

Francesco

Francesco,

What are your DO at the filler?  Specifically, coming right off the fill valve?  

When we commissioned our Comac Microbrew 10-2 last year we ran into irregular high DOs that happened whenever a filling head was bypassed. During the setup we were sometimes disabling certain fill heads that needed adjusting, and when we did other heads would see large spikes in O2.<o:p></o:p>

<o:p> </o:p>

I don't have all the details of the diagnosis, but it was related to a programming or timing issue in the control of CO2 to the bubble breaker and/or undercover gas. The machine was intending to shut off and save CO2 when no can was present in the seamer, because of the filling head bypass, but its aim was off and other heads ended up going through without CO2 being supplied. Comac fixed the timing under the hood and cleared up the issue.<o:p></o:p>

<o:p> </o:p>

This probably isn't related to your situation, if gas should be feeding all the time, but if you have flow indication you could try to see if gas is flowing when it should as well as at the right flow rate. <o:p></o:p>

------------------------------
Michael Harrison
Brasseur de Montréal
------------------------------