Philly Sour was born and raised in Philadelphia in the US. This is a yeast that was discovered by Matthew Farber and his team at the University of Sciences in Philadelphia. Philly Sour is an isolated wild yeast that has had testing over several years due to its very special characteristics.
For more information on the specifics of sour beer brewing check our Sour Beer Brewing Part 1.
All About Philly Sour
Philly Sour provides a flavorful balance of stonefruit, red apple, and peach flavors via fermentation. And at the same time produces lactic acid that leads to the souring effect. Another very useful trait is that it’s also very hot tolerant. Overall this yeast is a very exciting discovery as it greatly simplifies sour beer production. Before this yeast got its commercial name it was known at gY7b.
In the fermentation process when using Philly Sour yeast lactic acid is produced within the first 4 to 5 days from pitching. And this will produce a sour bed of between 3.2 to 3.5 PH so it should suit most peoples tastes. This strain is blessed by a high attenuation rate. Meaning that will need a high level of sugars in your wort and it’s happy at temperatures between 68 to 77F making it easy for most people to ferment.
Another thing is that it flocculates very strongly. So you can expect this to clean up very nicely in the glass resulting in a clear beer even when used with wheat or oats. This yeast is suited to various different sour beer styles. But it’s not yeast to co-pitch as it is a slow fermenter and will quickly be overtaken by other strains. What you can do is use it for the first 4 to 5 days so that the lactic acid is fully produced. You can then add another yeast to finish things up for a different effect or ester profile.
Lengthy trials have been conducted with Philly Sour and it has been found that due to the nature of this yeast and the way it behaves standard cleaning methods are enough without concern of contamination.