Increasing Hop Utilization

We all know that increasing the tempurate, aggitation, surface area and volume are all ways to increase the efficiency of extracting the most alpha acids from our hops. Therefore, a rolling boil with pellet hops in a full sized batch of low gravity wort will usually yield the best results. I’ve been thinking of ways to further increase the efficiency that we get from the hops we use. How to squeeze a bit of extra oomph out the little green guys?

We cannot increase temperature without increasing pressure or decreasing volume. Since we cannot thin water with anything remotely tasty, we must increase pressure. A pressure cooker is the ultimate tool for this. We can achieve 15 psi with most pressure cookers giving you an approximate boil temperature of 250ºF (depending on elevation and the current atmospheric pressure). We can add fresh water (1.000!) to further increase our efficiency by using a lower gravity medium. The downfall with this method is volume. You can usually only fit a gallon or two in a pressure cooker and most batches use upwards of 7-8 gallons of water to brew. With this, we can start off the hops before we even finish the mash. Boil the hops in the pressure cooker while the mash is going, then when we need some hop water to mash out. Add the boiled bitter water and hop sludge to the mash to reach the right temp (~170ºF). Then send it on to the kettle. This will yield a wort that is already high in bitterness extracted from the hops. Some of the hops will also go back into the kettle to boil again for an hour or more, thereby extracting even more. The rest of the hopping process continues as normal.

Do you think this would extract any undesireables or add a unique flavor to the beer? Would this work out to be more efficient than standard methods of extracting bitterness?

Well--I think you need both the acidity of the wort and the boiling temperature to isomerize the alpha acids so that might be a problem. I’ve made some hop tea just for drinking. It always tastes very grassy so that won’t taste so great in a finished wort.

I gotta tell ya--this is an interesting experiement but I’m glad you’re doing it and not me. I think I will just be satisfied to pay an extra buck a batch for more hops.

http://ift.confex.com/ift/2004/techprogram/paper_25787.htm

"Maximum solubility of alpha acids in a pH 5.2 buffered aqueous solution was 90ppm. Hop isomerization kinetics examined over a broad range of temperatures showed a rate coefficient of 0.0153(1/sec) for atmospheric boiling conditions. At 70deg C, less than 10% of alpha acids were converted in a 90 minute boil. At 120deg C, only 30 minutes were required for 90% conversion, with subsequent loss of iso-alphas to degradation products following. Activation energy was determined to be 36.375 kJ per mole."

The important point in the article that you cite, and this is something that Frank mentioned above, is that maximum solubility of alpha acids occurs at pH 5.2. Perhaps one modification you could make would be to acidify the water with a little phosphoric acid or lactic acid before putting it in the pressure cooker.

Another thing I just noticed is the people in the article say that the iso-alphas begin to degrade after 30 min at 120 C. Looks like there is a chance that you can cook these guys a little too much.

Originally posted by porterdog
The important point in the article that you cite, and this is something that Frank mentioned above, is that maximum solubility of alpha acids occurs at pH 5.2. Perhaps one modification you could make would be to acidify the water with a little phosphoric acid or lactic acid before putting it in the pressure cooker.

Another thing I just noticed is the people in the article say that the iso-alphas begin to degrade after 30 min at 120 C. Looks like there is a chance that you can cook these guys a little too much.

Here is some info from hopunion on bitterness and aroma

They are fractionating hop oil down to spicy for mouthfeel and floral for aroma.
What if we pull a vacumn on our boiling hops therefore lowering the boiling point will we extract more aroma then bittering

Originally posted by beerhandy
Here is some info from hopunion on bitterness and aroma

They are fractionating hop oil down to spicy for mouthfeel and floral for aroma.
What if we pull a vacumn on our boiling hops therefore lowering the boiling point will we extract more aroma then bittering

I wonder: Boiling more than 90 minutes can lead to better utilizatio of alpha-acids but also higher co-humolone levels and some serious grassiness; so will boiling at higher temperatures do the same thing.

On a side note, this sounds like an experiment for Budweiser, not a homebrewer. Who cares whether you get full utilization when you can pay as little as $5 for a pound of cascades?

Oh yeah, it’s good to see that your posting again Jordan. We need more creative souls like yourself in this Orwellian forum.

I wonder what would happen if you boiled some wort in the pressure cooker instead of just water? Would you get some different caramelization reactions at the higher temperatures?

A local brewer dry hopped a batch of his IPA, kegged it, and then treated that with supercritical CO2 (basically he pressurized the keg at something like 800 psi (don’t ask how the keg didn’t explode, but it didn’t). Anyway the beer was very grassy and sort of dank tasting. Oakes liked it, but I was a bit less impressed.

Originally posted by erway
I wonder: Boiling more than 90 minutes can lead to better utilizatio of alpha-acids but also higher co-humolone levels and some serious grassiness; so will boiling at higher temperatures do the same thing.

On a side note, this sounds like an experiment for Budweiser, not a homebrewer. Who cares whether you get full utilization when you can pay as little as $5 for a pound of cascades?