Waters 2414 differential refractometer

The specific gravity, alcohol level and pH of samples were determined from the centrifuged and degassed fermentation samples using an Anton Paar density meter DMA 5000 M with Alcolyzer Beer ME and pH ME modules (Anton Paar GmbH, Austria).
Concentration of fermentable sugars (glucose, fructose, maltose and maltotriose) was measured by HPLC using a waters 2695 separation module and waters system interface module liquid chromatograph coupled with a waters 2414 differential refractometer (Waters Co., Milford, MA, USA). An Aminex HPX-87H organic acid analysis column (300 × 7.8 mm, Bio-Rad) was equilibrated with 5 mM H₂SO₄ (Titrisol, Merck, Germany) in water at 55°C, and samples were eluted with 5 mM H₂SO₄ in water at a 0.3 mL min⁻¹ flow rate.

80 mL-scale fermentations were carried out in 100 mL Schott bottles capped with glycerol-filled airlocks. Yeast strains were grown overnight in 25 mL YP-Maltose (4%) at 25 °C. The pre-cultured yeast was then inoculated into 80 mL of 15 °P all-malt wort at a rate of 1 g fresh yeast L⁻¹. Fermentations were carried out in triplicate at 25 °C for 15 days. Fermentations were monitored by mass lost as CO₂. Samples were also drawn throughout fermentation and analysed with HPLC to monitor sugar consumption.
Concentrations of fermentable sugars and dextrin were measured by HPLC using a Waters 2695 Separation Module and Waters System Interphase Module liquid chromatograph coupled with a Waters 2414 differential refractometer (Waters Co., Milford, MA, USA). An Aminex HPX-87H organic acid analysis column (300 × 7.8 mm, Bio-Rad) was equilibrated with 5 mM H₂SO₄ (Titrisol, Merck, Darmstadt, Germany) in water at 55 °C and samples were eluted with 5 mM H₂SO₄ in water at a 0.3 mL/min flow rate.