Ask The Brewmasters

Hi Everyone,

We have used a mobile canning company for years, but over the last few runs, say the last six months, we are getting little mold or mildew spots on the cans, sometimes on the outside of cans, sometimes along the seam under the packteks. It's not every can, or even every SKU, but having to break down, inspect, and clean every case is making us insane. Cardboard case trays are unaffected, and guest cans, non-alcoholics, kombucha and so on don't appear affected.

So, do we think this is more likely to be a problem with:

• The rinse shower and air knife of the mobile canning line, either being insufficient or improperly set, and if so, is there something we can do to 2x check it or improve it on our end?
• Relative humidity and condensation on the cans after filling and stacking. We have been wrapping the pallets, forking them into the cold room, and unwrapping them for storage over there to improve drainage
• Some particularly pernicious mold has taken root in our cold rooms and the problem lies there? In which case, we have taken all unnecessary cardboard out, we take everything out and clean the walls, ceiling and floor annually, but there's no way we'll ever effectively sanitize every little bit of our cooling fans and evap coils, so what can be done? 

Any advice appreciated, this is a new one that has been bedeviling us this year. 

Hi Everyone,

We have used a mobile canning company for years, but over the last few runs, say the last six months, we are getting little mold or mildew spots on the cans, sometimes on the outside of cans, sometimes along the seam under the packteks. It's not every can, or even every SKU, but having to break down, inspect, and clean every case is making us insane. Cardboard case trays are unaffected, and guest cans, non-alcoholics, kombucha and so on don't appear affected.

So, do we think this is more likely to be a problem with:

• The rinse shower and air knife of the mobile canning line, either being insufficient or improperly set, and if so, is there something we can do to 2x check it or improve it on our end?
• Relative humidity and condensation on the cans after filling and stacking. We have been wrapping the pallets, forking them into the cold room, and unwrapping them for storage over there to improve drainage
• Some particularly pernicious mold has taken root in our cold rooms and the problem lies there? In which case, we have taken all unnecessary cardboard out, we take everything out and clean the walls, ceiling and floor annually, but there's no way we'll ever effectively sanitize every little bit of our cooling fans and evap coils, so what can be done? 

Any advice appreciated, this is a new one that has been bedeviling us this year. 

Hi Everyone,

We have used a mobile canning company for years, but over the last few runs, say the last six months, we are getting little mold or mildew spots on the cans, sometimes on the outside of cans, sometimes along the seam under the packteks. It's not every can, or even every SKU, but having to break down, inspect, and clean every case is making us insane. Cardboard case trays are unaffected, and guest cans, non-alcoholics, kombucha and so on don't appear affected.

So, do we think this is more likely to be a problem with:

• The rinse shower and air knife of the mobile canning line, either being insufficient or improperly set, and if so, is there something we can do to 2x check it or improve it on our end?
• Relative humidity and condensation on the cans after filling and stacking. We have been wrapping the pallets, forking them into the cold room, and unwrapping them for storage over there to improve drainage
• Some particularly pernicious mold has taken root in our cold rooms and the problem lies there? In which case, we have taken all unnecessary cardboard out, we take everything out and clean the walls, ceiling and floor annually, but there's no way we'll ever effectively sanitize every little bit of our cooling fans and evap coils, so what can be done? 

Any advice appreciated, this is a new one that has been bedeviling us this year. 

Hi Everyone,

We have used a mobile canning company for years, but over the last few runs, say the last six months, we are getting little mold or mildew spots on the cans, sometimes on the outside of cans, sometimes along the seam under the packteks. It's not every can, or even every SKU, but having to break down, inspect, and clean every case is making us insane. Cardboard case trays are unaffected, and guest cans, non-alcoholics, kombucha and so on don't appear affected.

So, do we think this is more likely to be a problem with:

• The rinse shower and air knife of the mobile canning line, either being insufficient or improperly set, and if so, is there something we can do to 2x check it or improve it on our end?
• Relative humidity and condensation on the cans after filling and stacking. We have been wrapping the pallets, forking them into the cold room, and unwrapping them for storage over there to improve drainage
• Some particularly pernicious mold has taken root in our cold rooms and the problem lies there? In which case, we have taken all unnecessary cardboard out, we take everything out and clean the walls, ceiling and floor annually, but there's no way we'll ever effectively sanitize every little bit of our cooling fans and evap coils, so what can be done? 

Any advice appreciated, this is a new one that has been bedeviling us this year. 

Hi Anonymous,

This often occurs during humid, hot weather. This combined with cold beer causing cans to sweat leading to mold growth. Maybe you have been experiencing unusually hot and damp weather? If so, a few of possible solutions might be (1) Warm fill or warm the cans after filling to above dew point (2) Store beer in a dehumidified warehouse (< 60% RH?). Speak to an HVAC specialist (3) don't stretch wrap pallets and leave space between them until they equilibrate to ambient conditions.

Good Luck

Dan Carey

New Glarus Brewing

Hi Everyone,

We have used a mobile canning company for years, but over the last few runs, say the last six months, we are getting little mold or mildew spots on the cans, sometimes on the outside of cans, sometimes along the seam under the packteks. It's not every can, or even every SKU, but having to break down, inspect, and clean every case is making us insane. Cardboard case trays are unaffected, and guest cans, non-alcoholics, kombucha and so on don't appear affected.

So, do we think this is more likely to be a problem with:

• The rinse shower and air knife of the mobile canning line, either being insufficient or improperly set, and if so, is there something we can do to 2x check it or improve it on our end?
• Relative humidity and condensation on the cans after filling and stacking. We have been wrapping the pallets, forking them into the cold room, and unwrapping them for storage over there to improve drainage
• Some particularly pernicious mold has taken root in our cold rooms and the problem lies there? In which case, we have taken all unnecessary cardboard out, we take everything out and clean the walls, ceiling and floor annually, but there's no way we'll ever effectively sanitize every little bit of our cooling fans and evap coils, so what can be done? 

Any advice appreciated, this is a new one that has been bedeviling us this year.