This is a common point of differentiation between brewers. Some people are avid 3-week brewers while others are on the shorter side of brewing in the 10-14 day range. For all of our Mr. Beer Refills, we recommend a brewing time of 10-14 days and we do that for good reason.

It is a common misconception that leaving your beer in the fermenter for an extra week, beyond the initial fermentation will make it better the opposite is true.

When your yeast is eating away all those sugars in your beer, it is producing C02. Once the C02 is produced it will race to the top of your fermenter and push its way out through the air ventilation notices that are cut into the lid of your LBK.

What this is doing is creating positive pressure in your LBK. This is creating a protective barrier that prevents oxygen from getting into your fermenter and ultimately your beer. Oxygen creates an awfully bad off-flavor in your beer. Your beer will come out tasting stale and often taste like cardboard.

So when you let your beer go longer than the 14 days, for example, 21 days you are increasing the risk of getting your beer oxidized.

 Once the yeast has eaten up most of the sugars that are in your beer, it will be creating less C02. Thus, reducing that positive pressure in your LBK and opening up the risk of oxygen getting in.

So that is why we suggest all refills be brewed in 10-14 days.

Now we know there are exceptions for everything. If you are brewing at much colder temperatures than the 68-76 degrees that we recommend your yeast will work slower and it may need more time to ferment.

If you are adding a ton of extra fermentables to your beer such as honey, or brown sugar or extract booters, etc. It may take longer to ferment all those sugars out.

That is why on some of our bigger recipes that we create we do recommend you brew it for 21 days. The more sugars that are added, the longer the yeast will need.

If you are brewing any of our refills just as is, then you only need to brew them for 10-14 days.

Cheers,

Robert