Alpha Acid Testing

[haz66]

Found this artical at

In the Back Yard
A gardener's guide to homegrown hops
By Patrick D'Luzansky © 1997



We can improve on this guess with a taste-testing technique I call "ratiometric titration." The approach here is to compare a same-cultivar hop of known alpha content with our unknown alpha hop. We compare the ratio of quantities of sugar needed to overcome the bitterness and infer that this ratio will equal the ratio of alphas. Thus, if it takes five teaspoons of sugar to offset the bitterness of our homegrown hops and three teaspoons to null the commercial hops, then our hops are five-thirds as strong, and our alpha-acid content is five-thirds the commercial alpha. If the commercial alpha is 6 percent, then our alpha is 5/3 times 6, or 10 percent.

I make up two hop tea samples - one from our unknown alpha fresh hops, and the second from commercial whole leaf hops of the same cultivar with known alpha. Stir one-quarter ounce hops plus one teaspoon sugar into two cups of boiling water (the sugar is needed because the hop resins are nearly insoluble in plain water.) Next, reduce the heat and simmer with the lid on for 30 minutes. Now add enough boiled water to each sample to bring their volumes back to two cups. Let the teas settle and cool to room temperature. Next, decant and filter the teas through a coffee filter to remove sediment.

Now comes the tasting part. It's best to do the tasting in the morning when your taste buds are freshest. Measure a quarter cup of each of the hops teas. Now taste a few drops of the unknown alpha tea and rinse off your tongue. The tea will taste bitter, of course. Next, add one-quarter teaspoon sugar and taste. It will taste a little less bitter. Continue titrating the tea with the sugar in quarter-teaspoon increments (and doing a tongue rinsing between each tasting) while tasting for the point when the predominantly bitter taste finally gives way to a sweet taste (with bitter overtones). This is when the bitter loses its bite. Record the amount of sugar it took to reach this turning point. Now repeat the titration with the known alpha tea. The ratio of the titrated sugar for the unknown hops to the sugar required for the known hops is our estimate of the ratio of the alphas of the respective hops.

Might not be the scientific way but it may help.

[yashicamat]

Interesting thoughts. Might try that with the 8g of fuggles which (I have no idea why) I've kept for 4 months out of the freezer to see how much (if any) bitterness is remaining.

[brewboy4]

Im looking for samples for alpha acid analysis. Hutton institute in Scotland would be carrying out the analysis. Contact me if interested