When it comes to brewing an American Porter, the choice of yeast plays a crucial role in determining the beer's flavor profile and overall characteristics. While both ale and lager yeast can be used to brew a porter, ale yeast is the most commonly used and recommended option. In this case, I would suggest selecting a yeast strain that enhances the desired qualities of a porter, such as a rich and full-bodied mouthfeel, while also providing the necessary fermentation characteristics.
One popular choice for brewing American Porters is an English-style ale yeast. These yeasts are known for producing flavors and aromas that complement the malt-forward nature of porters. They tend to accentuate the malt sweetness and contribute to a smooth, balanced finish. Some examples of English ale yeast strains that work well in porters include Wyeast 1098 (British Ale), White Labs WLP002 (English Ale), or Safale S-04.
Another option is to use an American ale yeast strain, which can add a unique character to the beer. These yeasts typically produce clean and neutral flavors, allowing the malt and hop profiles to shine. They tend to attenuate well, resulting in a drier finish compared to English ale yeasts. Some popular American ale yeast strains suitable for brewing porters are Wyeast 1056 (American Ale), White Labs WLP001 (California Ale), or Safale US-05.
When choosing a yeast strain for an American Porter, it's important to consider the desired level of attenuation. If you prefer a fuller-bodied beer with more residual sweetness, selecting a yeast strain that isn't too attenuative is crucial. This will help retain some of the malt sweetness and contribute to a rich mouthfeel. On the other hand, if you prefer a drier and more attenuated porter, a yeast strain with higher attenuation can be used.
Personal experience has taught me that using an English-style ale yeast, such as Wyeast 1098, can result in a wonderfully balanced American Porter. The yeast's fruity esters and malt-enhancing characteristics complemented the robust malt backbone of the beer, resulting in a smooth and flavorful brew. However, I have also enjoyed using American ale yeast strains like Wyeast 1056, which provided a clean and crisp finish to the porter, allowing the hop flavors to shine through.
There is no definitive answer to the question of which yeast is best for brewing an American Porter, as it ultimately depends on personal preference and the desired flavor profile. Both English and American ale yeast strains can produce excellent results, so it's worth experimenting with different strains to find the one that best suits your taste. Ultimately, the key is to choose a yeast that enhances the malt character, contributes to a full-bodied mouthfeel, and complements the overall flavor profile of the porter.