Y. KATAYAMA (1), T. Iimure (1), T. Kurihara (1), Y. Kozaki (1), S. Tamura (1), T. Nakamura (1);
(1) Sapporo Breweries Ltd., Yaizu, Japan
Technical Session 5 - Foam
Monday, June 15
10:45 a.m.–12:00 p.m.
Flores 1–2
Foam is one of the most important properties of non-alcoholic/alcoholic beer. We worked on improvement of wort foam stability to improve the foam quality of non-alcoholic beer containing malt and hops. As a result, the foam stability of the wort was dramatically improved by adding substances released from the yeast. Foam quality is affected by many factors such as raw materials, process conditions, and yeast. Yeast plays both positive and negative roles in foaming. It releases foam-negative substances such as lipids, ethanol, and proteases. Conversely, yeast-derived compounds such as mannoprotein are involved in foam formation and stabilization. In this study, yeast cultivated without malt and hops was suspended in distilled water. The suspension was centrifuged and the supernatant was freeze-dried. The dried extracts were then mixed with the hopped wort (10 mg/L). The wort with or without yeast-derived substances was carbonated. Foam stability was measured using the NIBEM test. The NIBEM values for the wort increased by more than 150 sec when yeast-derived substances were added. There was no effect when yeast extracts were added to the final beer, presumably because yeast-derived substances in the beer were sufficient. In Japan, 0.00% non-alcoholic beer is popular with consumers. However, it is not always easy to develop alcohol-free beverages using yeast. Our studies indicate that yeast extracts improve wort foam stability without adding viable yeast into the wort. Therefore, it will be easier to accomplish both alcohol-free and improvement of foam stability in non-alcoholic beer. We are now investigating the mechanism of the wort foam stabilized by using yeast. The understanding of the mechanism may contribute to the elucidation of foam formation during beer fermentation as well as development of non-alcoholic beer.
Yuta Katayama received his M.S. degree in agricultural chemistry from Tohoku University in 2007 and joined the Product and Technology Development Center of Sapporo Breweries Ltd. From 2007 to 2009, he mainly evaluated malts and hops using the pilot brewing plants. Since 2009, he has worked in the Frontier Laboratories of Value Creation and studies the gushing phenomenon, foam stability, and so on.
