The first step in making cheese is to separate milk into curds and whey. The curds go on to become cheese but the whey has traditionally been regarded as a waste product, perhaps fed to pigs or even dumped. In recent decades, industry has figured out how to turn the whey into various valuable products, including alcohol.
Recall that to make alcohol we have to ferment sugar. Whey contains 4-5% lactose, a kind of sugar, so that's a good start. It turns out, however, that very few yeast strains are up to the job of fermenting lactose. Milk far more readily turns sour, which is due to the conversion of lactose to lactic acid by bacteria.
Also, the low concentration of lactose in whey gives a low alcohol concentration and thus distillation cost is high.
It was an Irish company that first figured out how to make potable alcohol commercially from whey: Carbery, in Cork. Carbery is a dairy ingredients company which, in the 1970s, happened to be owned by Grand Metropolitan. Grand Met was able to chip in distilling expertise from its spirits subsidiaries. (Grand Met eventually transformed itself entirely into an alcoholic drinks company and merged with Guinness in 1997 to form Diageo. Carbery was bought out by four local dairy co-ops).
They isolated an efficient yeast strain after much research in the lab and convinced themselves they could reproduce the experimental yields at full scale. They put 6 full-scale fermenters and a 6-column still into operation in April 1978 and built in extreme flexibility, since it was the first plant of its kind and they did not know what problems they might encounter.
As far as I can make out, fermentation is preceded by ultrafiltration to remove the whey proteins (a useful product in its own right) and reverse osmosis to eliminate much of the water. By this means, the concentration of lactose is increased. After fermentation, a wash of about 3.5% ethanol is obtained which is then distilled to 96% ABV, the maximum achievable in a column still.
That's going a little further than allowed under whiskey rules, where the maximum is 94.8%, in order to ensure some flavour from the original grain remains. I'm not sure, then, whether there is any trace of whey flavour left at this point. Doubtless for some applications the closer to neutral alcohol the better. But I'll revisit this point in another article.
The venture was entirely successful and the "Carbery process" was subsequently licensed to plants in the US and New Zealand.
|The Carbery plant (from Google Maps)|
How to order it in a bar
Whey alcohol turns up discreetly as an ingredient in drinks like Irish creams. Though these are described as blends of cream and whiskey, they are topped up with whey spirit to reach the desired ABV percentage. This tones down the whiskey's contribution to the taste.
If whey alcohol was sold on its own, what would it be called? It could be termed vodka, since in the EU vodka can be made from any agricultural raw material, including whey. That would have to be indicated on the label though, a requirement for any non-traditional source (ie not grain or potatoes).
It can also be labelled as Irish Poitín (or Irish Poteen) if made in Ireland, since the EU definition of this spirit drink does not demand that it derive from any particular raw material.
The poitín label suits better than vodka, I think, because this spirit is thoroughly Irish. It's a product of our native dairy industry. The process for making it commercially was first developed in Ireland. It's made in Ireland by an Irish-owned company. The vodka requirement to declare the raw material on the label would be a good one to carry over though.
Is there a whey spirit tradition?
I've been looking for indications that whey was distilled, or even fermented, traditionally in Ireland. Obviously milk was readily available and it's the nature of humankind to turn anything to hand into alcohol if at all possible.
For some reason, cheese making waned in Ireland after the medieval period. Butter was the preferred method of preserving milk. (I haven't discovered if it's possible to turn buttermilk into alcohol.)
Despite the lack of cheese makers, someone must have been curdling milk because the Farmhouse Cheeses of Ireland book mentions that whey was often drunk with various additives, including honey and alcohol. Whey with sherry or madeira was known as sack whey or wine whey, usually served warm, and was regarded as a nourishing drink for the poorly.
I've described above some of the challenges of turning whey into alcohol. There is a dairy farm in Scotland that pulls it off on a small scale. The website is a little short on detail. It only mentions fermentation, not distillation but somehow the owner achieves an ABV of 12%. It's also matured in oak casks for a year.
He calls it "blaand", a traditional Scottish drink. The references to that in some 19th century books I've found online describe it as a sour whey. More acid than alcohol, I would guess, in those days.
I have failed, moreover, to find in these old books any mention of turning whey into spirits, in Ireland or Britain.
Whatever was the case in the distant past, we are certainly turning whey into spirits in huge quantities today. Carbery is pumping out close to 10m litres of ethanol per year. Some of that is for quaffing, some is further refined to 99.9% ABV and added to Maxol petrol.
From 2015, the EU will remove its caps on milk production in Europe. Carbery anticipates its local milk suppliers will increase production by up to 45% between 2015 and 2020. Whey hey.
I feel we have hardly begun to explore the possibilities of this other native spirit. It is a topic I shall return to in a future article when I will venture to describe how it actually tastes.