IBU compounding in freeze distillation?

Can't help you out with exactly with the proposed question, but I will say that you really do not want to use a lot of hops for an eisbock. I did one a year ag and it turned out great. I believe I only used 5-7 grams? For the 2 gallon batch. You don't it bitter!!

 

When Ive done eisbocks the hop bitterness definitely does not concentrate

I dont think he is gonna do much using dry ice, all he is gonna do is create localized cold spots that dont really achieve the effect he is going for

It would be better to toss a full keg outside when its down below zero for a night or longer

 

You don't want to back into an Eisbock. It is not an easy brew and the style demands a really good attention to detail. If your Bock is not spot on your Eisbock will be a hot mess. So really start with a great Bock and go from there. I do mean great, not adequate.

Has your friend made a decent 18% beer previously? Because that is something that those of us with decades of experience can't do reliably.


Bitterness will not be compounded very much by freeze distillation. Almost the opposite, the increase in alcohol will increase the malt profile and really increase the alcohol (obvious). Increasing alcohol will result in a sweeter beer. Much like a strong stout or barley wine, an Eisbock can quickly become an alcoholic mess of sweet malt and alcohol if the recipe is not spot on. And any minor flaws can become major if the base beer is not very good if not superb.

To be honest anyone attempting an Eisbock should have a very good Bock beer down cold first. Eisbock seems like a simple brew but it is really one of the more difficult styles to achieve with very little room to hide. A mediocre Bock is tolerable but it will make a miserable Eisbock. With all the effort it is best to go into it well prepared.

Brewers that focus on the ABV above else tend to fail. Eisbock is not an adventure in freeze distillation though it seems like the main thing. Eisbock is a concentrated Bock, not a concentrated ABV bomb.
Cheers.

 

I second all of what Billandsuz said

Making a good doppelbock is very challenging, you would think with all the malt that there is room to hide but there is not even a little bit. I still remember my first attempt years ago that I didnt have enough alkalinity in the water to balance the little bit of dark colored malts I used and it was absolutely horrendous

Couple that with a high abv target of 18% which is always tricky, let alone doing it to a lager and youve got the makings of a mess

why doesnt he brew a normal strength doppelbock and concentrate that? if he still wants more booze you can always supplement with high proof stuff in the keg. This approach seems a bit more manageable

 

I would think @stealth should be included in this conversation.

 

If all that you guys are doing is looking to push the envelop for ABV Ive got you beat (for the original un-eis'd beer that is) at 21.5% ABV verified with a GC

 

The links with all of that info are in @ryane's post.

 

As someone who cranks the radio up when the song comes on, I approve of the name.

 

Can't help you out with brewing an eisbock or the notion of ibu compounding, but I've got some excellent tips I can provide on high gravity brewing. I've used the following technique to successfully make beers in the 14-15% abv range (that didn't taste like a hot mess) using only chico yeast (a strain rated to only ferment up to about 11.5% abv)

1. Make sure the initial post boil wort going into the fermenter is no stronger than 22p (1.092sg) so that you don't create osmotic pressure / stress the yeast out, and oxygenate heavily along with pitching yeast nutrient and a proper yeast pitch (15-20 million cells per milliliter). NOTE: The 22p recommendation is from "The Bruery" and it's what I follow, although Stan Hieronymus claims you can push it to 25p (1.106sg)

2. Pick a yeast strain (or strains) to pitch that are alcohol tolerant, but avoid "super high gravity yeast" whenever possible as it makes every beer taste like garbage in my experience.

3. Ferment on the colder side of the suggested fermentation temperature range for your yeast strain (to combat ester and higher alcohol formation).

4. When you are about 60-66% attenuated, start adding your simple sugar additions (i like candi syrup because its already in liquid form and should be aseptically packaged). If you are going for huge abv (15%+), then only add roughly 4 gravity points per day of simple sugar until you have enough sugar to potentially hit your target abv. If you are going for the 12%-14% range, I've successfully added all of the simple sugar needed in one shot after the beer was 60% attenuated.

5. If you are lucky enough to have a conical fermenter, recirculate your wort for a while after adding the sugar. This will accomplish a few things. It will properly mix the sugar and wort, it will break naturally absorbed co2 out of the wort (which is stressful on yeast), and it will rouse the yeast. You can even add a little bit of extra yeast nutrient with the sugar and a tiny amount of oxygen at the end of the recirculation (despite being more than 24 hours into fermentation at this point).

5. Condition your beer. It probably won't taste as good straight out of the fermenter as it will in 6+ months from then. Although I have used the above technique to make 14-15% abv beers that do taste great right out of the gate!

As you can see, the process just requires very healthy and happy yeast. Which means low osmotic pressure, breaking co2 out of solution, rousing yeast, giving them the nutrients and oxygen they need to grow, and allowing them to ferment most of the maltose before giving them easier sugars to chomp on.

 

Solid advice all around. I made an eisbock a few years ago. It was far more challenging to get it to ice in layers than i had imagined. If you drop the temp too fast, it just slushes. So, slow ramp first, then you have to get it below 0F for a long time to get clean separation. Polar vortex was our friend, took it to -15 F and did 2 seperate ice removals. The tanins concentrated in the ice, leaving the beer lighter.

Don't fret about hops, it's not a hop forward style, and aging mellows it a lot. Aging is required after ice. This beer took a full year.

This is a style best done if you live far enough north to get a REAL winter, meaning sustained subzero temperatures.

I don't agree with candy sugar to push abv on this style. You don't need to. Not appropriate. Wrong mouthfeel. We use malt extract to get high abv beers where we are volume limited.

 

Also want to agree with ryanne, there are better methods of high abv if that is the goal. The odds of pulling out ice that is just water aren't great. Kolmbacher is only like 10%. Other methods are going to be more reliable and easy to control.

 

Point appreciated. Please allow me to clarify by saying that my candi syrup suggestion was only advice for hitting super high abv's, not for eisbock in particular. I agree that it might take away from the body and mouthfeel typically associated with an eisbock. But when the OP says he wants to really push it by brewing an 18.5% abv base beer, I don't recommend adding additional maltose (dme) to get to that extreme fermentable sugar level since it's more challenging for the yeast to ferment additional maltose than simpler forms of sugar.

 

Yeah, this is all contingent on what his plan is. We used dme to get a doppelbock to 1.10. But, we got a larger mash tun and can do that all grain.

 

DME makes sense for maltier styles of a more traditional high abv range. The OP said he was shooting for 18.5%, which is closer to 1.150 SG! When you added DME to your 1.10 doppelbock, did you add it to the boil or to the fermenter? With DME, I'd generally prefer to add it to the end of the boil than in primary. I don't have much of a thoughtout scientific reason for that though, just a gut reaction that gives me a preference. But doing so adds all of the gravity to the wort prior to fermentation which, depending on how high that is, can create lots of osmotic pressure and stress the yeast out leading to a potentially stalled fermentation.

When it comes to adding simple sugar, I try to avoid adding it to the boil kettle unless the addition is less than 10% of the total fermentables. In my experience, you can get away with 10% sugar addition in the kettle without risking a stalled fermentation. So if I need to add more than 10%, I'll due up to 10% at the end of the boil and the remainder in the fermenter after high krausen. This is all a precaution to encourage the yeast to ferment as much maltose as possible before adding the simple sugar. Often when adding too much simple sugar to the boil kettle, the yeast will gorge on all of that first, then move onto the maltose but get there fill before finishing it.

 

Bu:gu ratio shouldn't change, if anything I would expect the perceived bitterness to decrease...