Can I reduce the ABV of a recipe?

[Fletch]

I had a few bottles of Brewdog Punk IPA this weekend, and I love the taste. The only problem is, it's 5.6% and I prefer lower ABV beers, around 4-4.5%. I found a recipe on Beersmith, but it's even higher at 6.4%. My question is, can I just brew it with less grain, without significantly affecting the taste? Do I need to adjust the hops at all? I would be grateful for any guidance you can give me.

 

[Leon103]

Less grain will give you less sugar therefore less ABV.

 

[nbpicklesno2]

If you reduce the grain, it will indeed reduce the sugars and therefore alcohol.
However it may not taste balanced. You may also want to reduce the hop bill by the same percentage as you have reduced the grain bill. Put it all into beersmith (or whatever) to find what's going on. There is nothing wrong with not reducing the hop bill, but it I'll be a different beer.

 

[clibit]

Well, it'll be a different beer anyway. I would only reduce the bittering hops, in order to maintain the gravity to bitterness ratio.

For example, if you want to reduce the strength of a recipe that has an OG of 1050 and 40 IBUs, you should keep the 50:40 ratio. Bitterness in this example is 80% of the gravity. Reducing the OG reduces the malt sugars, so you need to reduce the bitterness to maintain the balance. So if you take it down to 1040, the bitterness needs to be 32 IBUs. (32= 80% of 40)

 

[rodabod]

You could try mashing high, like at 69c or even 70c. I'd avoid the temptation to use a lower attenuating yeast such as S-04 like I did if you go for a high mash temp as it seemed to struggle eating any of the more complex sugars... US-05 or similar suits the Punk IPA style.

Plug your numbers into Brewers Friend or similar.

 

[clibit]

Yes, good idea rod, if you mash at 69 you will boost the body and sweetness to offset the drop in strength, so could maybe leave the bitterness alone, or drop it less, at least.

 

[Fletch]

Many thanks for your suggestions folks. I'll give them a try and report back when I've done it. May be a while though; I've ingredients for three more brew before I buy the right stuff for the 'Punk' brew. I was just intrigued to know if it was possible. I seem to like the taste of the IPA's but I like a lower alcohol content. Might also try a clone of my other favourite, Jaipur, using the ideas you've suggested. Thanks again.

 

[rodabod]

Jaipur is documented in Mitch Steele's IPA book, by the way. Super beer.

 

[steveshep8676]

Hi Fletch, reducing the ABV isn't difficult the fermentables in a wort never change so if the water is evaporated the wort is more concentrated so higher SG. The same applies to adding water the ferment ambles are diluted so reducing the SG. Please read my notes below if you have any questions get back to me. Just a bit of background information, I did a professional brewing course in Sunderland at Brewlabs and have read extensively on all aspects of brewing since. I'm in Chesterfield so not too far from yourself, I'm currently building a HERMS system at home. It's a huge undertaking and so far cost me around £12,000 so I've taken a large step into the world of brewing. Hope below makes sense if not get back to me.
Hitting Target Gravity

Evaluate the total gravity during the brewing process and use it as a guide in adjusting the wort to the exact gravity you want. Remember that total gravity is the product of wort volume multiplied by its measured gravity in gravity units. As an equation, it is stated thus:
Total gravity = GU × Volume gallons

An important characteristic of total gravity is that it doesn’t change as you boil or dilute your wort. The only way to change the total gravity is to add fermentable materials such as malt extract, honey, or sugar to the wort.

By knowing the volume and gravity of the starting wort and the expected final volume of the boil, you can tell what the gravity of the wort will be at the end of the boil. Thus:

Total gravity (beg. of boil) - Total gravity (end of boil)

Because this is true, you can also say that

GU (beg.) × Volume (beg.) = GU (end) × Volume (end)

This restates total gravity in terms of the factors that determine it. If you now divide both sides of this equation by volume (end), you get an equation for estimating the final gravity of the brew. Thus:

GU (beg.) x Volume (beg.) = GU (end)
Volume (end

Say you have 8 gallons of runoff from the mash. The specific gravity of this wort is 1.038. You plan to boil long enough to yield 5.5 gallons of finished beer. Because the total gravity will not change during the boil, you can calculate the finishing gravity of the boil:
(38 GU × 8 gallons) ÷ 5.5 gallons 55.3 GU

This calculation tells you that this wort will have a gravity of 1.055 when boiled down to 5.5 gallons.
------------------------------------------------------------------------

In this example, I have set the terms “beginning” and “end” according to a specific brewing process that starts with excess volume and reduces it during the boil.

If you begin your boil with 4 gallons of wort with a specific gravity of 1.060, what will the specific gravity of the wort be once it is added to the fermenter and diluted to 5 gallons?
Use the same equation: [GU (beg) × Volume (beg) ] * Volume (end) = GU (end) but define “beginning” as the conditions in the boil pot and “end” as those in the fermenter.
Thus [60 × 4] ÷ 5 = 48 GU or 1.048

(60SG X 4gallon) ÷ 5 gallon = 48GU (1048)

I hope that makes sense?

 

[nbpicklesno2]

£12000!!!!! Whao. Your beer must be really good.

 

[martinjamesford]

Great info Steveshep, I don't want to hijack the thread but would you recommend the Brewlabs? I'm considering it myself.

 

[Gaspode]

I acknowledge I am a complete novice so happy to be told what I think is b****cks but would it be easier to remove the alcohol after making the beer by heating it and evaporating the alcohol in the same way as cooking?

Alcohol will boil at about 78 degrees C I think, so if the finished beer was heated to this temp the alcohol would evaporate off the liquid, well, in theory it would and the longer the heating the more would be driven off.

I guess this might effect the overall taste of the beer so you might then need to add a few more hops for flavour or something,(again, novice speaking to insert own method here). Or it might make for a more intense flavour, who knows, it might even ruin a completely decent beer and be a total waste of time.

It was just a thought.

 

[ezraburke]

I acknowledge I am a complete novice so happy to be told what I think is b****cks but would it be easier to remove the alcohol after making the beer by heating it and evaporating the alcohol in the same way as cooking?

Alcohol will boil at about 78 degrees C I think, so if the finished beer was heated to this temp the alcohol would evaporate off the liquid, well, in theory it would and the longer the heating the more would be driven off.

I guess this might effect the overall taste of the beer so you might then need to add a few more hops for flavour or something,(again, novice speaking to insert own method here). Or it might make for a more intense flavour, who knows, it might even ruin a completely decent beer and be a total waste of time.

It was just a thought.

It would, if i'm right, ruin the flavour especially the dry hops added (again, being a Brewdog clone i'm presuming there is a buttload of dry hop going on).

Probably best to reduce the malt bill and hop schedule as suggested. Easiest option i'd say.

 

[Fletch]

Many thanks for all the advice guys.

 

[brumbrew]

Mind = blown! I need to get some books and retake a level maths. I just wing it 😎

 

[Fletch]

Finally got this brew going today, 23L batch, using 4.2kg of MO. For the first time, I had a stuck mash on my Grainfather, and I'm trying to work out why. The only thing different I can think of is that I got my grain from the Home Brew Co. Ireland, whereas I normally use The Worcester Hop Shop. Maybe the Home Bre Co mill the grain finer? Has anyone else had similar problems?

I also noticed that the wort is much muddier than usual. Normally, it's pretty clear by the end of the mash. Maybe for the same reason?