Extracting Hop Aroma And Flavour With Pressure

[Nick JD]

...solubility of alpha acids in water at varying temperatures to work out what % of alpha acids you are removing by steeping them first. While you are at it you could see what the difference in solubility is when the 'steeping' solution used contains sugars/proteins etc.

Cheers
DrSmurto

Will do. At the moment my experience tells me "some", but not much at all of the AAs leach into the fermenting beer from contained dry hopping. A small enough amount as to be less than my tastebuds can discern.

But I'd like to know the numbers too as you've said with what's in the solution and how this changes things.

A very simple experiment could easily be done by letting say, 20g of hops steep in 5L of water for 4 days and then boil it for maybe 20 minutes. If there's perceivable bitterness then the AAs are coming out. If not, they ain't. Perhaps steeping them in fermenting beer (with an alcohol content) might leach more AAs...

 

[drsmurto]

I suspect that alpha acids are reasonably soluble in water even at room temperature.

They need to be in solution for the isomerisation to occur and whilst hot water would increase their solubility i doubt there is such a difference in solubility that it doesn't dissolve at all at room temperature.

Given there is no quick way of measuring the AA content of homegrown hops this is something that would be hard to quantify at home.

A side by side test would be the way to go, one using recycled hops and the other using new hops keeping every other variable the same.

 

[Nick JD]

...i doubt there is such a difference in solubility that it doesn't dissolve at all at room temperature.

It's a bit less than half (40mg/L @ 25C; 60 @ 100C). Which begs the question, why aren't beers made using these "recycle" methods completely unbitter?

Can it have something to do with the inefficiencies in extraction and isomerization?

EDIT: figures are for humulone - beta acids are nearly insoluble.

 

[Bribie G]

When I first started doing it I did a pure single hop lager with New Zealand Hallertau Aroma flowers and got good bittering, however the crunch would be using the same hop in pellet form and comparing the bitterness, as no doubt lupulin got hidden and trapped in the bracts.

 

[MHB]

Dr S

There is a strong link with pH, the lower the more soluble most of the interesting hop products are.

MHB

 

[JonnyAnchovy]

If you use massive pressures and liquid CO2, you can extract pretty much all the hop oils and acids - just like the big boys do. I'd love to see someone tackle the construction of a machine for producing CO2 hop extract at home.......

 

[bum]

I thought we made our own to get away from that "signature" flavour profile?

 

[MarkBastard]

The easiest solution is to buy hops at cheaper prices and in bigger quantities from overseas and not worry about spoilage <_<

 

[ekul]

Supercritical co2 extraction at home is not possible, unless you are an engineer i suppose. You need to have high pressure and temp to keep the co2 in a liquid phase, which is very tricky because typically co2 doesn't have a liquid phase, it sublimes from solid to gas.

You could probably extract all the bits you want with supercritical butane but you'd have to make sure the butane was pure.

 

[bradsbrew]

Anyone tried using an espresso machine to make a 'hop tea'?

Don't they work with high pressure hot water passed through a material? Seems like it could be ideal.

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Wont be trying it again. The beer never lost that grassy taste. Although I dont think the keg got past 2 weeks either.

Brad

 

[Bongchitis]

Supercritical co2 extraction at home is not possible, unless you are an engineer i suppose. You need to have high pressure and temp to keep the co2 in a liquid phase, which is very tricky because typically co2 doesn't have a liquid phase, it sublimes from solid to gas.

You could probably extract all the bits you want with supercritical butane but you'd have to make sure the butane was pure.

Yep thats right. Here is my butane unit.

 

[Bongchitis]

and apart.

 

[JonnyAnchovy]

I thought we made our own to get away from that "signature" flavour profile?

The CO2 extract is very different from isohop, I think. lots of our favorate beers use it (i.e. Three Floyds IPAs, DFH IPAs, Brewdog IPAs etc....)

and apart.

dude - that's so ******* cool. Have you done a post showing how it works?

I want to build one, purely as an excuse to use 'supercritical' more often in my daily lexicon.....

supercritical.

 

[JonnyAnchovy]

and apart.

View attachment 40981

a quick google has just revealed the other, more naughty uses for this....... Still - ever tried it with hops?

 

[Bongchitis]

a quick google has just revealed the other, more naughty uses for this....... Still - ever tried it with hops?

No... What are hops?


Get a can of pure butane from camping store. Fill vessel with hops h34r: Push can into hole at top with finger on bottom hole. Hold until you can't hold anymore and release finger. Butane spirts out the hole into a high walled vessel underneath (try it with a dinner plate I dare ya). Pop another can on top when 1st one is used and continue discharging until the butane runs clear. The butane boils off in seconds yielding hop oil.

Please don't do this inside or you will be on the news for all the wrong reasons.

The butane appears to be quite selective in its extraction yielding pure oils with no chlorophil or sugars etc that are present in tinctures. Dilute oil with ethanol to a workable consistency.

 

[ekul]

Did you make that or buy it? Very coool little unit. What brand of butane do you use?