What is the purpose of top fermentation?
Top fermentation is a method used for fermenting wort, and it is one of the ways to produce delicious and flavorful beer.
Furthermore, it provides the following results:
Higher alcohol content, lower sugar levels
Enhanced flavor development
There are several key factors associated with this method:
Use of top-fermenting yeast
Warm fermentation temperatures
Traditionally performed in open fermenters
ACE high-quality beer fermentation tanks
Which types of beer are top-fermented?
Brewers refer to the yeast used in top-fermented beer as top-fermenting ale yeast. In fact, the terms “ale” and “top-fermented beer” are often used interchangeably.
Are all ales considered top-fermented beers?
Based on common knowledge, all ales are generally considered top-fermented beers due to the yeast used. The yeast used in ales is similar to the yeast found in bread, wine, and other fermented foods.
However, there are some exceptions, such as Altbier and Kölsch, which fall somewhere between the categories of ales and lagers. These beers undergo fermentation at lower temperatures, similar to lagers.
Are lagers considered top-fermented beers?
No, lagers cannot be classified as top-fermented beers. They are brewed using bottom-fermenting yeast.
Unfortunately, beers are often categorized into two major groups: ale or lager, based on whether they use top- or bottom-fermenting yeast. While there are exceptions, most beers can still be classified within these basic groups.
What is open-top fermentation?
If you want to try an old-school fermentation method, you can opt for open-top fermentation. As the name suggests, this method involves fermenting the beer in an open environment, as opposed to closed fermentation in sealed vessels. It takes advantage of the natural behavior of top-fermenting yeast.
In the past, wide and shallow pans, also known as “coolships,” were commonly used for open-top fermentation of moderate-sized batches.
Open-top fermentation vs. closed fermentation
While open-top fermentation may seem appealing, it has both advantages and disadvantages compared to closed fermentation.
Here is a quick comparison:
Open Top | Closed | |
Yeast Reusability | Easily accessible and harvested since it is open | Requires yeast washing |
Ease of Contamination | – Use filtered fresh air to prevent contamination of large batches – Watch out for insects and vermin | If the vessel remains sealed, the chance of infection is minimal. |
Carbon Dioxide Management | Natural or mechanical exhaust is necessary for large batches | CO2 can be easily piped for disposal or storage |
Outgassing | Undesirable gases escape readily | Restricted airflow increases the chance of reabsorbing undesirable gases |
Possible Spontaneous Fermentation | Yes, if required for extended periods | No |
