Malt whisky from Indian six-row and two-row barley

Six-row and two-row are different plants

Look at an ear of barley from above. In two-row barley, only the central grain at each node develops, so you see two rows of plump kernels. In six-row barley, all three grains at each node develop, giving six rows. The side kernels are often smaller and a little twisted.

Most barley grown in India is six-row, sown as a rabi crop in the winter and harvested in spring in states such as Rajasthan, Uttar Pradesh, Haryana, Punjab and Madhya Pradesh. Two-row malting varieties have been bred for Indian conditions, including at the Indian Institute of Wheat and Barley Research in Karnal. These are grown in smaller volumes. Our guide to Indian six-row barley for malt whisky goes deeper on the crop.

What changes in the grain

The typical differences, compared with good two-row malting barley:

• Protein. Six-row usually carries more protein. More protein means less starch per kernel.
• Husk. More husk relative to grain. Good for lautering, but husk adds no alcohol.
• Enzymes. Higher diastatic power. Six-row malt converts starch readily.
• Kernel size. Less even, which makes steeping and milling harder to get right.
• Extract. Usually lower, because of the higher protein and husk.

None of this makes six-row unusable. It makes it different. Plenty of brewing traditions use six-row malt successfully. American brewers have used it for generations, often alongside corn or rice adjuncts that lean on its spare enzymes.

Extract drives spirit yield

For a distiller, the number that matters is litres of pure alcohol per tonne of malt. Scotch distilleries working with modern two-row varieties commonly aim for around 400 litres of alcohol or more per tonne. Lower extract malt gives fewer litres per tonne, so six-row whisky usually costs more grain per litre of spirit.

Do your costing with your own maltster's analysis, not a Scottish benchmark. Ask for extract, moisture, protein and diastatic power on every lot. A malt with 2 or 3 points less extract changes your spirit cost per litre. Our guide to Indian single malt covers how this feeds the finished product.

Adjust the mash for six-row

Six-row malt's strengths can be used. Its extra husk forms a looser grain bed, which helps run-off in a mash tun or lauter tun. Its higher enzyme content gives more room for error in conversion. Distillery mashes are not boiled, so the enzymes carry on working in the wash back, which helps convert dextrins into fermentable sugar.

The floor detail we would insist on: set your mill gap on the actual lot, not on last year's setting. Uneven six-row kernels mean a gap that cracks the plump grains can leave the small ones whole. Whole kernels are lost extract. Check the grist by sieving a sample at every new lot.

Higher protein has a flavour side

More protein means more nitrogen in the wort, which feeds yeast and affects the fermentation's by-products. Some distillers find six-row gives a heavier, more cereal or nutty new make. Others find little difference once cut points and fermentation are tuned. Treat it as something to taste and measure rather than something to assume.

Run a small trial if you can: one wash from six-row malt and one from two-row, same yeast, same fermentation time, same cut points. Compare yield and new make side by side.

Work with the maltster early

Indian malting capacity for distilling grade malt is limited. Most of it serves brewers. Talk to your maltster before harvest about the variety, the protein range you want and the analysis you need with each delivery. Store malt cool and dry: Indian humidity raises malt moisture quickly. Damp malt loses quality and invites insects. Our guide to barley contracts for malt whisky covers the commercial side.

Choosing barley, reading a malt analysis and turning it into a yield forecast is basic distillery work. It is also where many new distilleries lose money without noticing, which is why a structured distilling course covers it in detail.

Your first step: ask your maltster for the full analysis sheet of your last lot and calculate the litres of alcohol per tonne you actually achieved against it.