The isomerization of humulone into isohumulone is a process that is not fully understood. When the hops are boiled the humulone within is isomerized into isohumulone, Figure 4. The amount of humulone isomerised depends greatly on outside factors like boiling time, temperature, pH, and sugar content. It is our goal to identify the time it takes for isomerization and the factors that affect and change this, especially the factors that vary as a part of the brewing process.
F.R. Sharpe and I. H. L. Ormrod, in their 1991 article, developed a method to extract humulone into an o-phenylene diamine/ humulone complex. They did this using a re-crystallization technique. To further extract the humulone from the o-phenylene diamine complex they used a separatory funnel with a combination of solvents. UV absorbance spectras were taken to confirm the compounds, Figure 5. These two processes may be used to extract humulone for further experimentation.
Humulone rotates polarized light at -212° per g/mL, also known as its optical rotation. Cis- and trans- isohumulone have an optical rotation of 46.7° and -7.8° respectively. Knowing this, we can calculate the amounts of cis- and trans- isohumulone using a polarimeter during and after isomerization.
The US patent 3,354,219, a Method for Preparation of Isohumulone Concentrates, describes a method to isolate isohumulone from hops. They do this by refluxing DI water, hops, and NaOH and then adding HCl to crash out the organics. Isohumulone attaches to the organics and also crashes out. The organics are then filtered and then put in a separatory funnel with hexanes, H2SO4, and methanol. The organic layer is then collected and purified to obtain isohumulone. We can use this to obtain isohumulone to take an H NMR for comparisons to other compounds.
The US patent 3,354,219, a Method for Preparation of Isohumulone Concentrates, describes a method to isolate isohumulone from hops. They do this by refluxing DI water, hops, and NaOH and then adding HCl to crash out the organics. Isohumulone attaches to the organics and also crashes out. The organics are then filtered and then put in a separatory funnel with hexanes, H2SO4, and methanol. The organic layer is then collected and purified to obtain isohumulone. We can use this to obtain isohumulone to take an H NMR for comparisons to other compounds.
Purpose: We are doing this in order to better understand the isomerization of humulone into isohumulone to better the brewing process.
Hypothesis: We should be able to extract humulone from hop oil using the same method as Sharpe and Ormrod. I also expect that humulone would isomerize into isohumulone when in the presence of a base.
Hypothesis: We should be able to extract humulone from hop oil using the same method as Sharpe and Ormrod. I also expect that humulone would isomerize into isohumulone when in the presence of a base.