The Englishman George Watkins wrote a brewing manual, The Complete English Brewer, in numerous editions in the second half of the 1700s. He advised to use elderberry juice in making porter as it emulated in home conditions (he said) the aging of a large bulk of porter in commercial breweries.
You can read the passage here, see especially pg. 129, in the 1773 edition.
It appears the dark red juice was favoured also for the colour it lent, but clearly the sharp fruity notes were meant to emulate the winy taste old beer can assume. Watkins advised to place the juice in the cask as conditioning was being completed, and he instructs to drink it within about 15 days from bunging. Presumably the juice would not ferment out completely in this time and thus lend its full flavour, as he refers to “good body” in the drink.
A few modern brewers have used elderberry in brewing. A U.K. brewer actually made a stout with it, the name escapes me for a moment but it was sold at the LCBO briefly. It was nice but the effect of the fruit was faint, at least to my palate. The local brewpub, the Granite, made an elderberry porter a few years ago. It was nice but the fruit didn’t as I recall contribute that much.
When I heard that Sapporo-owned Unibroue brewery in Quebec put out an elderberry wheat beer – another fruit spin on its Wit series called Ephémère – I tried to get a bottle as soon as possible. The reason was I assumed the juice was added at the end of fermentation, as for Watkins’ beer, and I wanted it fresh before the sugars were used up. Ephémère is unfiltered and some conditioning must continue in the bottle or so I assume unless it is pasteurized now, but I don’t think it is.
I was not successful in getting a bottle near release, which was 4-5 months ago. I did find one in Montreal last weekend, and here is my impression.
The fruit notes were noticeable and in this case the flowers of the plant were added which contributed a Muscat note as the bottle labelling states. Withal it was akin to adding a dash of cranberry juice to beer. You get something sharp and fruity at the same time, a racy red fruit edge.
This element in porter would emulate lactic acid production from bacterial microflora in the aging vessels or brewery environment. Port was sometimes added to stout in Britain, and other fruity things, perhaps all an echo of the 18th century aging and blending methods which made for a sharp estery drink. The Black Velvet, a combination of Champagne or cider with stout, is broadly similar.
Finally, I added the glass shown to a Black Velvet I made, a blend of perry, Russian Stout, and black lager in this case. It was very good, the fruity or sharp parts from the wheat, pear, and elderberry blended well with the sweet malt and hops.
I wonder though if the elderberry taste in the Unibroue was muted after some five months aging. Certainly the colour lasted, as you see in the image.
You can buy elderberry juice, the ones I’ve seen are blends with cranberry. So just adding that to porter should make a Black Watkins, I’ll dub it. For hyper-authenticity, it should be added to a nearly full bottle of unfiltered porter or stout, stoppered and left to sit for two weeks. I may do this soon.
Caution re elderberry: based on my reading, the variety generally used for wine and jam both here and in Europe is not poisonous but most types of the genus are. This means the fruit should be cooked to ensure safety. Watkins’ juice almost certainly was a reduction by boiling and therefore had undergone heat treatment. I don’t know what Unibroue uses, but anyone proposing to make elderberry juice or a derivative product at home should ensure the fruit is cooked first.