Let us introduce you Tropical Illusion, which is a mango infused Berliner Weisse. This style is a traditional specialty of Berlin region. Napoleon’s troops called it “the Champagne of the North” due to its unique character. In Germany, it is classified as a Schankbier denoting a small beer of starting gravity in the range 7-8°P. Often served with the addition of a shot of sugar syrups, flavored with raspberry or woodruff. Has been described by some as the most purely refreshing beer in the world (BJCP). I didn’t want this beer to be mixed with any syrup, I added fruit myself instead.
BJCP 17A ABV: 2.8% – 3.8%
IBUs: 3 – 8 OG: 1.028 – 1.032
SRM: 2 – 3 FG: 1.003 – 1.006
The malt base of this style is quite simple: 50-50% of Swaen©Pilsner and WhiteSwaen©Classic. Souring fits well to other beer styles too, so there is no need to stick to this grain bill. If you want to have a sour version of other type, feel free to choose any as per your own taste.
There are many souring methods, this time I show you kettle souring. You still do the mash, lauter and sparge, but you shouldn’t perform a full length boil, only 15 minutes at most. A small amount of hop addition is preferred, as exceeding 15 IBU could limit the effect of Lactobacillus. For the same reason try to minimize oxygen exposure too. If there is any way, flush the head space of your kettle with CO₂ before adding Lacto. Set pH to ~4.5 by using some citric, lactic or phosphoric acid. Cool down your wort to the optimal temperature of your souring culture (30-35 ⁰C should be fine) and keep it for 24-48 hours. Your wort should be now around 3.5 pH and have a nice, tart taste. It’s time now to finish your beer as usual. Perform a full length boil, so Lacto will not be present in your fermentation and add some hops. For Berliner Weisse you can use any noble or citrusy one. However you also have a chance to make a hop forward beer, like a sour session IPA, by using much more and rather fruity hops. It’s up to you. Finally simply cool down, oxygenate, pitch yeast and let it ferment as usual.
Now you already have a nice, funky beer, but why would you stop, when you have the chance to give a fruity twist. If you don’t feel too comfortable, you can still
take a few liters from your batch to experiment with. First question is how much fruit you should add. Well, it’s up to the fruit. My suggestion is 50-200
g/l. Go for the lower end if you just need a slight fruitiness or your fruit is strongly flavored and add as much as you can if you have a mild-taste fruit.
Mango is in the middle I think, so I took ~100 g/l and had a moderate fruit aroma in my Berliner Weisse.
There are many options to add fruit to your beer. Which one to choose depends mainly on the fruit type and how strong fruit aromas you go for. On the
other hand don’t forget about the risk of contamination either. You can easily get rid of all yeast and bacteria on the fruit by performing the boil, but you
want to preserve flavors too. This could be challenging, so let’s see some options. First one is simply cut the fruit into small pieces and add in the
mash with the grains. As the fruit is present during the whole mash and boil, there is no possibility to spoil your beer, however due to the heat your
fruit aromas might be “boiled”. This method isn’t used very wide, but for pumpkin ales could be the best one. You can also add fruit during or after
the boil by using a hop bag. Heat kills all microorganisms, but also release pectin of the fruit, which may result haziness. To prevent this you can
perform a “whirlpool fruiting” by holding it for about 30 minutes at 70-75°C. The best timing however is adding them in secondary fermentation.
At one hand you won’t get any “cooked” taste, besides fruit aromas will not be lost. You have to deal with higher risk of contamination, but the current pH
and alcohol level will help you. Should you use fresh fruit, wash it, remove leaves, peel and seed. Then cut it into small pieces or make a puree with a
masher or a mixer. Using sterile commercial fruit puree could be also fine, but it could result off-taste. Some say letting it frozen results more juiciness.
Then put the fruit in the secondary fermenter and siphon the wort on it. If you wish to remove fruit solid easier, you can use a sanitized hop bag, but keep in
mind that the contact surface would be smaller then. Let it sit for 5-7 days before bottling, so then all the sugars will be fermented. Remove the fruit bag
or syphon out your beer, bottle and enjoy