ANSWER

Malt extract can be added and folded in when the sugar mass at around 130 to 135°C is transferred to the cooling table (Ziegler, 2007). Heating over for too long period (i.e. adding on at too early stage of processing) might be causing darkening and breaking down of malt extract (Ann Arbor Brewers Guild, 2009). According to Briggs (1998), a minimum of 49°C are needed to warm highly viscous malt extracts to permit them to flow. However, warm periods should be short to minimize darkening and flavor changes.

References

Ann Arbor Brewers Guild. (2009). The Herald Trubune. Newsletter of the Ann Arbor Brewers’ Guild, 23(4).

Briggs, D. E. (1998). Malts and Malting (pp. 1-796). ‎Heidelberg, Germany: Springer Science & Business Media.

Ziegler, H. (2007). Flavourings: Production, Composition, Applications, Regulations (pp. 516-518). Hoboken, New Jersey: John Wiley & Sons.