Is Philly Sour cheating with sour beer production? I don’t care, it works, it’s tasty, and it’s really easy.
One can make sour beers with kettle souring cultures. It’s slow. It’s a hassle. For a Berliner Weisse I once just added some lactic acid into the kettle after the boil to achieve the desired pH, skipping the step of souring with a live culture. It worked well, possibly lacking the more complex flavours, it was still good. Nobody spotted the difference.
I was rather excited to see the launch of Lallemand’s Philly Sour yeast in the summer of 2020. Lockdown meant that I didn’t have the help of the RAB to drink my beers, so a sour beer was on the production schedule… but it would have to wait for some room in the kegs. I’ve now had chance to brew with this interesting yeast.
I produced a double batch of Berliner Weisse wort. I split the wort equally into my two fermenters, and pitched the appropriate amount of yeast into each. The amount of yeast can make a big difference in how sour the beer is.
There are some tips for getting the best from this yeast, I’ll include them at the end… One of the other tips is when to add the fruit (if adding fruit). I added my fruit on day four. Into one fermenter went 1kg roast pineapple, into the other 2kg of homegrown rhubarb.
This yeast takes a little longer to ferment. About 10 days, even for my 3.2% ABV Berliner Weisse. We can see from the graph below taken from the Lallemand presentation that the yeast produces the acid first, then after a few days starts producing the alcohol. This is why I added the fruit on day four after most of the acid production, to get a good balance between acid and alcohol.
The other aspect that affects the acidity (sourness) of the beer is the yeast pitch rate. It seems that the pitch rate is more closely determined by the desired pH than it is to the OG of the beer. I pitched 22g (two packs) of yeast into each 22L of wort. This equates to 1g/L, the lowest recommended by Lallemand for optimal acid production.
So, the finished beers after conditioning and carbonation were delicious. You’ll have to trust me on that as we are still in covid restrictions and I can’t share them.
Here are some tips on brewing with Philly Sour, summarised from Lallemand’s YouTube presentation:
- Temperature is important. Keep the fermentation between 22°C and 27°C. The temperature of the fermentation seems to have minimal effect on the flavour profile. You can pitch at 30°C and fall to 25°C. Don’t ferment at 18°C – 20°C as it risks under attenuation. This yeast is very flocculant so risks dropping out at lower temperatures.
- Pitch rate is critical to the final pH. Between 1 to 1.5 g/L is best for acid production. Under or over pitching from this rate gives less acid.
- Great for fruit, especially mango and pineapple. Early addition of fruit adds acid, later addition adds alcohol. Adding mid fermentation (about day five) rouses the yeast and works well for a balance of acid and alcohol.
- Philly Sour doesn’t ferment lactose so this can still be added for sweetness if desired.
- Can pitch a second yeast AFTER primary sour (day four) for character. e.g. a Belle Saison for a more farmhouse and sour character. Don’t co-pitch on day one or the other yeast will dominate, overtaking the Philly Sour and you’ll get no acid.
Something else I’ve learned is that Philly Sour reacts to sucrose sugar. Simple malt wort with long chain sugars (higher mash temperature) gives more of a red apple flavour, whereas more sucrose (fruit sugars or low mash temperature) gives a stone fruit, peach flavour.
There’s a lot to learn with this novel yeast. Have fun experimenting.