Grapes are not a flavouring agent here. They are a fermentation input — one that carries its own wild microflora, its own acids, and its own sugars into the barrel. The result is something neither beer nor wine, and richer for it.
Adding grapes to a spontaneous ale is not a new idea. Lambic producers in Belgium's Pajottenland have been refermented on fruit for centuries — kriek on cherries, framboise on raspberries — using the fruit not simply for flavour, but as a secondary fermentation substrate that reshapes the beer from within.
At NINEBARNYARDOWLS, we take that principle further. We work with whole grape varieties — Chardonnay, Pinot Noir, Merlot, Pinot Gris — chosen for what each contributes chemically and microbiologically to the barrel, not just for taste.
Tartaric acid from the grape skin is the key structural element. Unlike lactic or acetic acid that already exist in the fermenting beer, tartaric is rare in brewing and brings a mineral, almost saline sharpness that no other ingredient provides. It interacts with the lactic bacteria already present in the barrel, nudging the final pH downward and sharpening the line between brightness and funk.
The grape skin also carries its own population of wild yeast and bacteria native to the vineyard — a second inoculation layered over our existing Gladstone microflora. This collision of two distinct terroirs is what makes our grape blends genuinely complex rather than simply fruity.
New Zealand's cool-climate viticulture produces grapes with naturally elevated acidity. For spontaneous ale blending, this is not a side note — it is the point.
The Wairarapa wine region sits at the southern end of New Zealand's North Island, at roughly 41°S latitude — equivalent in the northern hemisphere to northern Spain or central France. Harvest runs from late February through April, depending on variety and season.
Cool nights and warm days through the growing season produce grapes that retain acid longer than in warmer climates. When we add these grapes to barrels of spontaneous ale that are themselves high in lactic acid, the result is a fermentation environment of unusual complexity — multiple acid types interacting with a diverse microbial community.
This is not something that can be replicated with concentrate, extract, or warm-climate fruit. The Wairarapa's specific combination of latitude, diurnal temperature range, and free-draining gravelly soils is part of what ends up in the bottle.
The workhorse of our grape blends. NZ Chardonnay from cool sites carries green apple, lemon curd, and a chalky mineral quality that translates directly into the fermented ale. High natural acidity at harvest means significant tartaric acid input into the barrel.
We use Chardonnay as the primary grape in our Burgundy blend (75%), where its structural acidity provides the backbone that holds the blend together across extended aging.
Added whole-bunch in our Burgundy blend (25%), Pinot Noir brings strawberry and cherry aromatics alongside the tannin structure only available from red variety skin contact. The anthocyanin pigments contribute a distinctive blush colour.
Pinot Noir from the Wairarapa tends toward bright red fruit with firm acidity rather than the plummy softness of warmer-climate examples — an important distinction for blending into an already-acidic spontaneous ale.
Our Merlot blend takes a different approach. Merlot contributes softer tannins than Pinot Noir, and at NZ cool-climate sites carries dark plum, blackcurrant, and a faint chocolatey depth. The lower tannin grip allows more of the spontaneous ale's own character to show through.
The result is our most approachable grape blend — rounder, darker, and with a presence in the mid-palate that the Chardonnay-forward Burgundy blend does not attempt.
The most aromatic of our four varieties. NZ Pinot Gris carries stone fruit — white peach, nectarine, pear — alongside distinctive terpene compounds that give the grape its characteristic perfumed quality. These aromatics survive fermentation better than most.
Pinot Gris also adds textural weight through higher residual phenolics and its naturally oily mouthfeel — a quality that gives this blend a presence on the palate that its relatively pale colour does not suggest.
Grapes are added to the barrel after primary fermentation is established — not at the start. Timing matters as much as variety.
Primary barrel fermentation converts the malt sugars over the first six to twelve months. When whole grapes are added to the barrel, their glucose and fructose restart fermentation activity — feeding wild Saccharomyces and Brettanomyces populations that have been dormant as the original sugars were exhausted. This extends the active fermentation window and contributes additional CO₂ for natural carbonation at bottling.
Grape skins carry their own wild yeast and bacterial populations specific to the vineyard they were grown on. When these enter the barrel, they introduce microorganisms that were never present in the Gladstone air — a collision of two distinct microbial communities. Some strains will outcompete what is already there. Others will find a niche. The result is a more complex microbial succession than coolship fermentation alone could produce.
Spontaneous ales are typically high in lactic and acetic acids — both produced by bacterial fermentation of malt sugars. Grape additions introduce tartaric acid, which is largely resistant to bacterial conversion, meaning it persists in the finished beer as a distinct acid type. The interplay between lactic brightness, acetic complexity, and tartaric mineral sharpness is what gives our grape blends their layered acidity.
We add grapes whole rather than pressed. Whole-bunch addition gives us control over extraction rate — the skins release their tannins, colour, and microflora gradually as fermentation activity slowly breaks them down, rather than all at once. This produces a more integrated result where the grape element feels like part of the beer's structure rather than a layer sitting on top of it.
Not every barrel that receives grapes becomes a grape blend. After the addition and secondary fermentation, we taste every barrel individually. Some will have integrated the grape perfectly. Others will be dominated by a single element — too tannic, too aromatic, too reductive. The final blend is assembled barrel by barrel, selecting for balance, and only then do we consider the finished beer ready to blend and bottle.
Every bottle of our grape blends is the result of a harvest, a winter coolship, twelve to thirty-six months in French oak, and a single decision about which barrels belong together. The grape is where it starts. The blend is where it ends. The spontaneous fermentation is everything in between.
View Our Grape Blends