Tuesday Beer Trivia: John Palmer’s “How to Brew”

The following explanations were taken from How to Brew: Everything You Need to Know to Brew Great Beer Every Time by John Palmer.

Question 1: In First Wort Hopping, the hops steep in the hot wort as the boil kettle is being filled, which may take a half hour or longer. The essential (aromatic) oils are normally insoluble and tend to evaporate to a large degree during the boil. The idea is that, by letting the hops steep in the wort prior to the boil, the oils have more time to oxidize to more soluble compounds, resulting in more flavor and aroma being retained during the boil.

Question 2: Pitching rates definitely affect the ester character of the beer, however this is false. It’s actually the opposite – Lower pitching rates tend to produce more aromatics and esters than higher pitching rates. Lower pitching rates will encourage more yeast reproduction due to the perceived abundance of resources. The yeast will reproduce until the total yeast mass reaches the limit for what the wort resources can support.

Question 3: According to John Palmer, ¾ cup corn sugar per 5 gallon batch (19 L) will produce about 2.5 volumes of CO2 in the beer, which is pretty typical of most American and European pale ales.

Question 4: The Kolbach Index helps us understand the soluble-to-total protein ratio (or S/T ratio) which describes how well the endosperm has been opened to expose the starches to the amylase enzymes.

Question 5: Although 149°F (65°C) is generally recommended for best fermentability, it assumes that complete gelatinization has already occurred. John Palmer recommends adjusting your strike water to 153°F (67°C) for single temperature infusion mashes, the reason being that you will be better assured of complete starch gelatinization, and if the mash cools a few degrees during the mash your fermentability will only be enhanced.