Hop Steeping - a debate

[Tinkerer]

Then I looked up the boiling point of the main hop oils and found them all to be over 100C, yet received wisdom is that they are very volatile. Take the point that if you can smell it then it has a vapour pressure, but for it all to go in such a short space of time would at least be very surprising given the boiling points.

My feeling is the fact that oils tend to float and spread out on the surface makes them liable to be evaporated that much quicker. I've been doing some ad hoc Googling of my own on the subject and came across this in Beer - A Quality Perspective, Charles W. Bamforth, Ed. (http://www.scribd.com/doc/24820895/Beer ... erspective)

"Some workers have reported the loss of 95% of the total hop oil within 5 minutes of addition of the hops to a boil."

Another thing that is said to be important is oxidation of hop oil components (like humulene). This is a factor of heat and oxygen. So you might expect oxidation to be more prevalent with vigorous mixing at high temperatures, compared to dry hopping late during the ferment, where oxygen is scarce and the temperature is a lot lower. Some of the oxidation products have their own distinct aromas, but there seems to be some doubt as to whether they are there in high enough concentration to be detectable.

Sooooo complicated!!!

[Dr. Dextrin]

That makes some sense to me. People have reported oil slicks on the surface and that seems like potentially lost hop oils to me. Even if they don't evaporate, they'll probably get stuck in the hops and trub when you run off. Another question is, if the slick gets smaller/disappears, as it generally seems to, is that because it evaporates (bad), or because it dissolves (good)? I'd have thought that agitation (like when the wort is recirculated in a whirlpool setup, for example) might tend to favour dissolving the oils.

As to heat de-naturing the oils, that also seems likely to me. When I make wine, the ingredients often have to be steeped in water and I play about a lot with temperature and steeping time (and pH) because they affect the result considerably. I'd be surprised if hops were any different. You only have to note how the taste and aroma of most vegetables (e.g. brussels sprouts) changes as you cook them to realise there's some chemistry going on!

And don't forget that if you dry hop after the start of fermentation, there will be alcohol present, which is an excellent solvent, potentially capable of extracting compounds from hops that won't dissolve in the original wort prior to fermentation.

[Tinkerer]

That's a good point Dr. Dextrin, the alcohol during dry hopping must help dissolve the hop oils. Also, when it comes to steeping hops, the hop chemist guy in the interview mentioned glycoproteins that help dissolve the hop oils into the wort. So there will be a mixture of evaporation and mixing going on, and the oils that remain will at least partially be oxidised. Once oils are oxidised, they are likely to be more soluble as well. So loads of factors all going on, probably including ones that we haven't thought of yet...!

[Martin G]

Having been inspired by this thread I changed the way I make my hop tea. I used to pour boiling (boiled for 10mins) water over the hops, cover with flamed foil and wait for it to cool before adding to the fermenter. On the last two occasions I have let the water drop to 80C before adding the hops (Cascade). My perception is that I have much more aroma and it seems fresher and cleaner to me.

[orlando]

These are the sort of experiments I like to see, though I have never made hop teas before. I am currently steeping some dargkgrains for a stout and using cold water rather than hot to reduce the extraction of harsh tannins and acidity. Will add to the boil with 5 minutes to go. My expectation is that it will smooth out the flavour and promote the malt.

I would add about the cascade experiment it is a very pungent hop anyway so would like to hear if it boosts less aromatic ones.

[jonnyt]

The answer is simple. Go to a closed system such as cube hopping!

[soupdragon]

Well I've been doing the 80c steep for ages, and I've been continually disappointed in my hop flavour and aroma, considering the sheer amount of hops I've been chucking in.

Today I'm brewing a recipe quite similar to one I did a couple of months ago. I'm going to chill quickly and immediately while whirlpooling as best I can with a big spoon. Hopefully this will help dissolve all the hop oils before they scarper. The proof will be in the pint.

How did this actually turn out?

Cheers Tom

[Befuddler]

Well I've been doing the 80c steep for ages, and I've been continually disappointed in my hop flavour and aroma, considering the sheer amount of hops I've been chucking in.

Today I'm brewing a recipe quite similar to one I did a couple of months ago. I'm going to chill quickly and immediately while whirlpooling as best I can with a big spoon. Hopefully this will help dissolve all the hop oils before they scarper. The proof will be in the pint.

How did this actually turn out?

Cheers Tom

Not well. It got infected.

I've since built a new boiler which allows a completely closed system when chilling. The chiller coil is built into the lid of the boiler along with a recirculation pipe. I keep the lid on throughout the boil and just prop it open until I knock the heat off. This is giving me a fiercely strong boil akin to a commercial kettle and a much more quicker, more sanitary chilling process (gets down below 80c in about 2 minutes). I'm using a solar pump, so it doesn't have enough grunt to get a proper whirlpool going, but it is recirculating the whole batch through the hop bed while chilling. Hopefully the effect will be very similar.

This first batch from this new system has been in the fermenter since monday. It better be good!

[orlando]

Well I've been doing the 80c steep for ages, and I've been continually disappointed in my hop flavour and aroma, considering the sheer amount of hops I've been chucking in.

Today I'm brewing a recipe quite similar to one I did a couple of months ago. I'm going to chill quickly and immediately while whirlpooling as best I can with a big spoon. Hopefully this will help dissolve all the hop oils before they scarper. The proof will be in the pint.

How did this actually turn out?

Cheers Tom

Not well. It got infected.

I've since built a new boiler which allows a completely closed system when chilling. The chiller coil is built into the lid of the boiler along with a recirculation pipe. I keep the lid on throughout the boil and just prop it open until I knock the heat off. This is giving me a fiercely strong boil akin to a commercial kettle and a much more quicker, more sanitary chilling process (gets down below 80c in about 2 minutes). I'm using a solar pump, so it doesn't have enough grunt to get a proper whirlpool going, but it is recirculating the whole batch through the hop bed while chilling. Hopefully the effect will be very similar.

This first batch from this new system has been in the fermenter since monday. It better be good!

Is the kettle able to vent the steam OK, if not DMS is a distinct possibility. I brewed with a lid with a smallish hole in it and it just was not enough and the beer was slightly tainted by it.

[Befuddler]

Is the kettle able to vent the steam OK, if not DMS is a distinct possibility. I brewed with a lid with a smallish hole in it and it just was not enough and the beer was slightly tainted by it.

The lid is propped open throughout the boil, so yeah the steam can escape easily. I only close the lid when the heat goes off, and then the chilling is so rapid that DMS won't be an issue.

[soupdragon]

Not well. It got infected.

Losing one is never a good thing

I've since built a new boiler which allows a completely closed system when chilling. The chiller coil is built into the lid of the boiler along with a recirculation pipe. I keep the lid on throughout the boil and just prop it open until I knock the heat off. This is giving me a fiercely strong boil akin to a commercial kettle and a much more quicker, more sanitary chilling process (gets down below 80c in about 2 minutes). I'm using a solar pump, so it doesn't have enough grunt to get a proper whirlpool going, but it is recirculating the whole batch through the hop bed while chilling. Hopefully the effect will be very similar.

This first batch from this new system has been in the fermenter since monday. It better be good!

Sounds good. I 'm looking forward to the Mrs getting her new kitchen so I can make use of the wok burner. I might finally get a good rolling boil

Cheers Tom

[orlando]

Is the kettle able to vent the steam OK, if not DMS is a distinct possibility. I brewed with a lid with a smallish hole in it and it just was not enough and the beer was slightly tainted by it.

The lid is propped open throughout the boil, so yeah the steam can escape easily. I only close the lid when the heat goes off, and then the chilling is so rapid that DMS won't be an issue.

I knew you would have it covered, er if you pardon the pun.