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Soulshine 10-01-2012 06:12 PM

2 questions about brewing a very high gravity beer
I am aiming to brew a beer that will finish out at about 20% alc/vol.

1) The yeast strain I found, the owner of the home brew shop I use, says is good for up to 20-25% alc. Can I add all the sugars at once and if not, why?

1A) If I need to continually add sugar to the beer while it is fermenting, how do I get a true alcohol reading with my hydrometer. I can figure out the initial reading but what about each time I add more sugar? How do I factor that into the alcohol %?

Thanks for the help!

BigB 10-01-2012 06:31 PM

1. I wouldn't recommend it. You are likely going to be using simple sugars to get the ABV up that high. If you add all of the simple sugars up front, the yeast will likely consume those rather than the more complex sugars from the malt. Then they will likely crap out on you and not go back and chomp on the maltose.

1A. You can figure out the ABV just as if you added the sugar all at once. You will need to calculate what the ABV would be if all of the sugars were added at once. Then take an OG as usual prior to pitching. If this number is higher or lower than expected, you will need to compensate for your finish ABV by those points. But the simple sugars are going to 100% fermentable, so you can safely assume that their calculated SG addition will be accurate. For example: Say you are assuming that the wort itself will give you an OG of 1.085 and the simple sugars would add an additonal .050 for a total of 1.135. After the mash, you measure the OG and get only 1.080. You can still assume that your simple sugars would account for .050... so you would adjust your OG to 1.130 for ABV calculations.

I would start fermentation with a gigantic starter and just the malt. Then after 3-4 days of active fermentation, I would add about 1/2 of the simple sugars. Then 3-4 days later I would add the rest. Another problem with adding so much sugar at the beginning is that you could stress out the yeast. Even professional brewers have an extremely difficult time getting that much ABV, so I really wish you the best.

Kaiser 10-03-2012 02:19 PM

keep track of all the water, sugar and extract you are adding to the beer and then calculate the OG that the wort would have had. Use this as the OG for the alc% calculation when you have the FG.

Alternatively you can also spend money and send the beer to WhiteLabs for an analysis.

Or you can determine both apparent extract (the FG that you read with the hydrometer) and real extract. To get real extract you need to boil off the alcohol. To do that you take a beer sample of known weight, boil it down by half and then add water to get back to the same weight. Make sure to use this water to rinse all the sugars from the pot back into the sample. Then you test the gravity of that and there are formulas to calculate the OG from the apparent and the true extract of the beer.


MDVDuber 10-03-2012 05:51 PM

DogfishHead uses a number of sugar additions after the start of primary fermentation to get the 18% ABV or so of their 120 and World Wide Stout. Have a listen to the Can You Brew It episode for DFH 120 and you can hear how they went about doing it.

Soulshine 10-16-2012 05:40 PM

Thanks for all the info! Helps a bunch!

ajdelange 10-16-2012 06:24 PM


Originally Posted by Kaiser (Post 4465782)
To get real extract you need to boil off the alcohol. To do that you take a beer sample of known weight, boil it down by half and then add water to get back to the same weight. Make sure to use this water to rinse all the sugars from the pot back into the sample....

Nothing wrong with the concept of doing it gravimetrically but it is usually done volumetrically as that is easier. Fill a volumetric flask to the mark with cold beer. Use a pipet to suction off the foam that rises into the neck. Put the flask in a water bath and, when at equilibrium at 20 C, use the pipet to bring down to the mark (the beer will have expanded as it warms to 20). Now transfer quantitiatively to a distillation flask. "Quantitiative" transfer means that you rinse the volumetric flask with two 25 mL portions of DI water and transfer the rinsings to the boiling flask. Now boil until down to 1/3 the original volume. Turn off the heat and allow to cool. Transfer quantitatively back to the volumetric flask, fill up to the neck with DI water and put back in the water bath. When equilibrated make back up to the mark with DI water, stopper and mix thoroughly. Measure the extract of this 'reconstituted' beer and convert to specific gravity. The mass of the extract in the reconstituted beer is V*(Pr/100)*SGr*.998203 (r designates 'reconstituted'). This all came from the beer. The true extract is the number of grams of extract per 100 grams of beer. The mass of the beer was V*SGb*.998203 (b designates 'beer'). The true extract is, thus 100*V*(Pr/100)*SGr*.998203/V*SGb*.998203 = Pr*(SGr/SGb).

Note that this is the ASBC procedure (MOA Beer-5,A) for determining the true extract. It is usually done as part of the alcohol determination procedure in which the the 'steam' from the boiling is condensed and the density of the condensate measured in order to determine how much alcohol was in the beer.

[Edit] Upon reflection I guess whether the volumetric method is easier than the gravimetric (ASBC MOA Beer-5, B) would be a matter of personal preference. It may or may not be easier to bring volume to 100 mL than weight to 100 grams but if you are weighing you do not need to worry about temperature (no water bath required) and you don't have to do any calculations (other than converting SG to Plato if your instrument does not read Plato).

seth8530 10-20-2012 09:31 PM

Yup either do what he said to get exact as your procedure allows you to do or give my equation a glance. It should be able to tell you what your final abv is as accurate as a sg based abv calculation can be I do believe.


Soulshine 01-08-2013 12:59 AM

So finally did it and hit the 21% mark I was aiming for. Taste very close to dogfish 120 but has a very sweet corn sugar taste to it. Only been in fermenter 5 weeks. Will time kill some if the sweetness? Will the carbonation hide some of the sweetness? U hit my final gravity but just taste very sweet right now. Any suggestions?

Kaiser 01-08-2013 02:37 PM

I think you need to use a yeast that can metabolize the sugar at that alcohol level.


dstranger99 01-08-2013 02:43 PM

How exactly do you get a beer to such a high ABV? I can't seem to get past 5%, but the guy that runs my LHBS has made IPA's that go as high as 8%.........

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