Monday, 3 July 2017

One Solera, 2 Beers

Brewing a refill for
the LHBG solera.
Over the past 5 years I've maintained a series of solera's - two at home which, sadly, after 3 years of successful operation died to a bit of neglect on my part. The third belongs to my brew club, for whom I manage the solera. Starting this winter I am planning on a series of posts and videos about solera brewing, but as a bit of a prequel, I thought I'd share a brief post on by brew clubs solera (LHGB Solera) and two beers I prepared from the first pull out of it.

Firstly, for those of you who don't know, a solera is a method of continually producing sour beer. For a sour beer solera, a fermenter (often a large barrel) is filled with beer and allowed to ferment and age. At a set interval (usually between 6 months and 1 year) a portion of the solera is removed and bottled, and the solera topped off with fresh beer. Over time the effective age of the beer in the solera will approach a average age which will then be retained for the remainder of the solera's lifespan. For example, for the LHBG Solera, we remove half the beer every nine months, leading to a beer which will eventually converge on an effective age of 1.5 years. How effective ages are calculated, managing a solera, and other topics, will be the subject of some future posts.

The LHBG solera has been designed to be a middle-of-the-road sour beer; modest funk and restrained sourness. The beer is ~5% ABV, 50:50 mix of pilsner and wheat malt, and 10IBUs. This recipe was selected for a few reasons - the beer is aging in a white wine barrel, and this lighter tasting beer should allow for that character to shine through. Secondly, it allows members of the brew club a lot of flexibility in turning their share into something unique, through adding fruit, spices, or blending with other beers.

Refiling the LHGB solera.
The first time the solera was filled we brewed the beer on the personal brewing equipment of 10 volunteers, which was then pooled into the solera. The logistics of this wasn't trivial, leading our club to decide to build a large brew-rig to fill barrels (we have two at this time). Construction took a lot longer than expected (18 months), which was a happy mistake as it gave the beer a good bit of age on it, and got us to a point where we would have a solera with a stable effective age of 1.5 years. The first beer from the solera was a little more acidic than planned, and lacked brett character, so we tweaked the refill recipe to adjust. IBU's were increased to suppress sourness, performed a ferulic acid rest and fermented with a Belgian yeast to increase brett character, and finally, we added another sour culture to the mix to try and bring out a bit more complexity in the beer. These adjustments highlight the power of a solera - you can tweak a sour beer as it ages, to get a desired and consistent product.
Pellicle on the LHBG solera, as viewed during the refill.
A little over a month ago we "withdrew" the first beer from the LHGB solera, and shared the beer among interested club members. I am moving in the very near future, and has such had to do something quick with my share, as moving some carboys of sour beer are not really an option. Half of my share I bottled straight-up. The second half I put on some hibiscus for a week, whose fruit character should complement the sour beer nicely. The beer was bottled using sugar and champagne yeast, and left to carbonate for the past 6 weeks.

Straight Sour

Appearance: The unmodified (straight) sour beer pours with a thin and short-lived head. Body is golden in colour with a slight haze and a nice effervescence.

Aroma: Aroma is lactic with a notable white-wine note. Missing from the aroma is any hint of funk - no mustiness, leather or barnyard to be found.

Flavour: Up-front is a strong lactic tartness and a modest white wine character. Behind this is a bit of a bready malt character and a touch of hop bitterness. The flavours are a little unbalanced - the acidity is too high given the lighter nature of the beer, and this acts to hide both the wine and malt character. There is no brett funk at all in the flavour. There is also a slight off-flavour on the after taste; a touch of diacetyl which leaves a bit of butteriness on the aftertaste.

Mouthfeel: Acidic, crisp and dry. Aftertaste is a lingering acidity in the back of the throat, and a bit of a buttery sweetness.

Overall: Not bad for the first pull from a solera, as there has been no chances to correct for flaws yet, but still in need of improvement. Good news is that all the flaws are correctable, and on the re-fill we modified the recipe to give more brett character (which should also clean up the diacetyl) and to suppress the lacto to make it less acidic. I'm stuck with my share as-is, but if I had the time I'd blend this beer with a saison to cut the acidity, add some funk, while still allowing the white wine character to shine though.


Hibiscus Version

The choice to add hibiscus was based on a few factors. The first was speed - hibiscus was something I could add and bottle on time for our big move. The second was balance - hibiscus adds a sensation of sweetness (although not actual sugars) which can help to counteract the acidity of the beer. Finally, its floral/fruity flavour should complement the white wine character of the beer nicely.

Appearance: Strawberry-red, with a touch of haze. Unlike the straight solera beer, this one has some additional head retention, with a modest white head that lasts for a couple of minutes.

Aroma: Remarkable similar to the unmodified version; acidic with a touch of white wine. The aroma is perhaps a touch more fruity than the unmodified version, but only slightly so.

Flavour: This is where the big difference is. While still acidic, there is enough "sweetness" from the hibiscus to counter-act it somewhat. It is still a very sour beer, but is less harsh and better balanced than the unmodified version. This helps to bring out the white wine character, with the hibiscus acting to accentuate the berry character of the wine rather than acting as its own flavour. And while I know this is purely perceptive, I cannot detect the diacetyl note that is present in the unmodified version.

Mouthfeel: Dry, crisp and acidic. Despite the less acidic taste on the tongue, the beer still gives a lingering acidic burn in the throat. Aftertaste is an acidic berry character.

Overall: The hibiscus makes this a more balanced beer than the unmodified version, but as with the unmodified form, this one too has some flaws that will be corrected by adjustments to the solera's recipe.

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