Mangrove Jacks M15 Empire Ale Yeast 10g

M15 is an English ale yeast that produces the full-bodied, fruity, malt-forward character of classic British ales. High-flocculating and fast to clear, it leaves the residual sweetness and fruit complexity that English bitter, porter, and stout are built around.

Best Suited To

• English Bitter, Extra Special Bitter (ESB), English Pale Ale
• Porter, Stout, Brown Ale, Mild, Old Ale
• Any British ale where malt complexity and body are the point

Specs

• Fermentation temp: 18–22°C (lower end for cleaner profile)
• Attenuation: 70–75%
• Flocculation: High
• Alcohol tolerance: Up to 12% ABV
• Pitching rate: 1 sachet per 23L at standard gravity

When to Choose M15

Choose M15 over S-04 when you want more ester character and a fuller flavour. S-04 is slightly cleaner and flocculates more firmly; M15 produces apple, pear, and stone-fruit notes that suit richer English styles well.

Choose M15 over US-05 when you want British rather than American character — fuller body, more residual sweetness, and distinct fruitiness. US-05 is not the right yeast for a porter or ESB.

Practical Notes

Ferment at 18–19°C to keep ester character balanced. Fermenting above 20°C pushes M15 into stronger apple territory that works against the style. Keep it cool for the first few days of active fermentation.

Rehydrate in 10x its weight in 27°C water, or pitch directly. The high flocculation means the beer clears quickly without fining agents for most styles.

Keep refrigerated. Once opened, reseal and use within 7 days.

Reviewed by the AHB Brewing Team — June 2026.