Overgravity Brewing

[Bribie G]

My 20L no chill cube is a bit small to produce my 25 L brews (24 on bottling) I note that the 20L actually holds up to 22. If I'm going to do all the work for an AG brew I would prefer to get my full 24 L that I always got in my extract / partial / kits n bits brews.

OK I should get out the wallet and buy a 25L cube but haven't been able to get any from Bunnings and it seems a waste of a good 20L cube so I've been doing overgravity brews for my last couple and topping up in the fermenter with a couple of litres of good old water or half a bag of ice to get to pitching temp quicker. Also during the brew about half a litre would go in with a hop tea late addition and another half litre at Polyclar time.

Without doing extremely picky calculations I seem to be 'hitting the style' by nudging the ingredients - for example where I would use 4.5 kg grain I've upped it to 5, used a 30g hop addition instead of 25 and so on.

It's not really severe overgravity brewing like the commercials do but I'm interested to know if any other AHB members do this? I seem to be getting nice malty hoppy beers and no 'watered down' taste although I'm wondering if there's any way OG brewing alters hop flavour or aromas etc in the 'watered down' brew? (edit: as opposed to hitting the same gravity using the same ingredients in a 'normal' brewing process)

I also note that Fresh Wort kits seem to be brewed this way as they recommend adding some water.

 

[RetsamHsam]

I will be doing this with a mild I brewed yesterday, thread here.. I managed to increase my efficiency by over 20% on a 45L batch.. So I will be diluting with 15L to get it down to the gravity I want.

 

[Bribie G]

I will be doing this with a mild I brewed yesterday, thread here.. I managed to increase my efficiency by over 20% on a 45L batch.. So I will be diluting with 15L to get it down to the gravity I want.

Yes some relevant comments on the other thread, especially about bittering - which should be ok as long as we intend from the start to dilute with water.

 

[razz]

Been doing it for years BribieG. 40 lts into the kettle and 40 lts into the fermenter.

 

[buttersd70]

No problem michael, just do all your additions the same as you would for the larger batch size. If you enter the additional as top up water in Beersmith, you don't even need to work out any numbers, beersmith will do that for you.

btw if the cube is a willow, it will hold 24L....when it's sitting flat, and you fill to the point where it starts to overflow....thats 24L.

 

[RetsamHsam]

Yeah you're right.. I had no intentions of diluting it at mash-in, however when I measured my pre-boil gravity and it was afew points higher than my anticipated SG I quickly threw in some extra hops, and made a last minute decision to add a large-ish flame out addition..

I am abit worried that it will turn out alittle thin/watery due to the low SG (1.037).

Have you ever diluted with a low gravity beer? How did it turn out?

 

[buttersd70]

No probs at all...1037 is 1037, regardless of how it was achieved. That was your planned OG, and you mashed for that accordingly (I presume. ie 68-70C mash). Having a 1037 wort as a result of watering down your (unplanned for) high(er) gravity wort shouldn't make any difference.

edit: last time I did over grav, I diluted to 1036? from memory. Maybe 1038. Either way, it ended at 1012, same as my Milds normally do when brewed full scale.

 

[Jakechan]

I thought it would be achieved easily in Beersmith by doing the following (although I havent tried it).

Eg.

For an existing recipe of 20 litres batch size, scale it up to 25l (this changes the grist amounts etc).
Then in the main recipe window re-enter 20l in the Batch Size box.

Thus you end up with the grist/hops etc scaled up for 25 litres, but will be brewing it at the desired concentrated level and end up with 20l.
And the 5 litres to be added in the fermenter takes you back to where you want to be.

Is this what Beersmithers do?

Cheers,
Jake

 

[buttersd70]

I thought it would be achieved easily in Beersmith by doing the following (although I havent tried it).

Eg.

For an existing recipe of 20 litres batch size, scale it up to 25l (this changes the grist amounts etc).
Then in the main recipe window re-enter 20l in the Batch Size box.

Thus you end up with the grist/hops etc scaled up for 25 litres, but will be brewing it at the desired concentrated level and end up with 20l.
And the 5 litres to be added in the fermenter takes you back to where you want to be.

Is this what Beersmithers do?

Cheers,
Jake

If you go into equipment, you enter your recipe as if it was for the 25L...then you enter 5L in topup water, and it removes that from the boil volume. That way, it calculates your water requirements for 20L out of the kettle.
Simple. No need to over think it.

 

[Thirsty Boy]

No probs at all...1037 is 1037, regardless of how it was achieved. That was your planned OG, and you mashed for that accordingly (I presume. ie 68-70C mash). Having a 1037 wort as a result of watering down your (unplanned for) high(er) gravity wort shouldn't make any difference.

edit: last time I did over grav, I diluted to 1036? from memory. Maybe 1038. Either way, it ended at 1012, same as my Milds normally do when brewed full scale.

While its on topic, I would just like to give an upfront warning that the following post is stupidly geeky.... but I suspect people will find it interesting.

Ultra High Gravity brewing is a commercially accepted way of making "light" beers with flavour profiles that are closer tho those of "normal'" beers. Something happens to the levels of total flavour compounds in worts that are brewed and fermented at over 16 plato (about 1.064). basically the percentages graph gets steeper all of a sudden. This means that you can make a beer - dilute it by half and still get 2/3rds - 3/4s of the flavour compounds that would have been in a full strength beer. Here's a graph to illustrate - note, numbers not real... just for illustration of the concept OK



So you can see that a beer brewed at "normal" gravity with an OG of 9 plato (1.036ish) has significantly less flavour "stuff" than a beer of normal gravity (lets say 12.5 plato or 1.050) - BUT a beer brewed at 18plato and diluted to the same strength as the 9plato beer before packaging, has nearly as many flavour compounds as the "normal" beer does.

I can't for the life of me remember that actual numbers and I have exaggerated the steepness of the change to make it obvious - but its not that far out from what I remember was the real case. You could boost the TFC levels closer to the "normal" beer than to the low OG beer and win back more than half the flavour loss.

This was technique was once upon a time a Fosters trade secret - but everyone does it now. I'm wondering if there is a place for the technique in homebrewing?? Fosters doesn't really go above 18plato - efficiencies and other process realities start to make it not worth it... but it might be a way to make fantastic ordinary bitter or mild ale to have around in your keggerator.

Thirsty

 

[Online Brewing Supplies]

Hey Thirsty got a reference for the material, this type of question came up on an exam I had and I didnt know the answer.Actually there is not a lot of info on high gravity brewing around.Hope you find the reference.Like you said it is a trade secret.
GB

 

[Bribie G]

Yes CUB were the first brewery to bring out light beer in the early 80s, I remember Carlton 2.1 which was a very flavourful drop (we are talking true 'light' rather than mid... XXXX did the first mid but called theirs Lite which is confusing)



IIRC it was eventually 'replaced' by Fosters Light which to me wasn't as good.

Edit: ah and here's the one that came just before 2.1, wasn't too bad as well but it was the try out brand introduced about the same time as XXXX lite



I take it that whole segment is now only represented by Stirling? IMHO those earlier models were more drinkable.

 

[Thirsty Boy]

Hey Thirsty got a reference for the material, this type of question came up on an exam I had and I didnt know the answer.Actually there is not a lot of info on high gravity brewing around.Hope you find the reference.Like you said it is a trade secret.
GB

not really... I was in a class/training/junket session with Mick Jontef at work and he talked about it a little. Put up a graph pretty similar to the one I did and gave a verbal explanation. There were numbers... but I cant remember them. I left my book in the BDU and it might have had more, I will go and retrieve it when I go back to work on Monday an see if there is anything else.

From what I recall, the increase in flavour compounds above 16 isn't anything secret... it was a well known effect - it was only the utilisation of the effect in brewing low alcohol beers at Ultra High gravity that was a Fosters innovation. Like i said, no secret anymore. Common mega practice in Aus at least.

I think people have almost stopped talking separately about high gravity brewing (as opposed to ultra high) as if it were anything special. Nowadays its just so ubiquitous in large breweries that its simply "brewing" and it mainly gets a mention as a practice that allows better throughput volumes and tank utilization. Apart from that I think that the technical differences between brewing at 15 plato and brewing at 10.5 are considered to be so minimal that they dont rate a mention. The quality of the dilution water and how to exclude oxygen being far more important than the fact that the original beer was HG.

Bribie - maybe try the Carlton Light again. Its till out there unchanged after many a year. And it isn't brewed UHG - still an original first generation "light" and as a side snippet of info, an AG beer. No adjunct in Carlton Light.

I see if I can come across any more info on HG and UHG brewing for you Gryphon.

Thirsty

 

[Mantis]

Yes CUB were the first brewery to bring out light beer in the early 80s, I remember Carlton 2.1 which was a very flavourful drop (we are talking true 'light' rather than mid... XXXX did the first mid but called theirs Lite which is confusing)

View attachment 25413

IIRC it was eventually 'replaced' by Fosters Light which to me wasn't as good.

Edit: ah and here's the one that came just before 2.1, wasn't too bad as well but it was the try out brand introduced about the same time as XXXX lite

View attachment 25414

I take it that whole segment is now only represented by Stirling? IMHO those earlier models were more drinkable.

I dont remember the 2.1 but drank a lot of carlton light, before switching to tooheys gold, then to hahn blue.
Thankfully, I then caught on here and started the path to better beers, and now the dark side
(Or maybe the slightly shaded side BIAB)

 

[Bribie G]

Bribie - maybe try the Carlton Light again. Its till out there unchanged after many a year. And it isn't brewed UHG - still an original first generation "light" and as a side snippet of info, an AG beer. No adjunct in Carlton Light.

I see if I can come across any more info on HG and UHG brewing for you Gryphon.

Thirsty

Wow is it really..... that's mindblowing, since then I've brought up two boys to adulthood, voted for Bob Hawke (yup it's that long ago)... I might give Fosters Yatala a ring and see where I can get it and have a couple for old times sake. :icon_cheers: :icon_cheers:

 

[dr K]

LA (Low Alc not Los Angeles) was originally not a product of CUB but of Tooths in NSW. Carlton bought Tooths out.
There was a law in place up to some time in the 70's, under as I remember the Pure Foods Act or similar that required a product called "Beer" to be of a minimum ABV, this was dropped and the light beer brigade came swarming. Swan had a <1% beer at one stage.
Carlton Light was certainly available in 1979, maybe early 1980 perhaps and was from my limited tasting agreeable.
XXXX Gold at around 3.5% was available in Qld in 1980.

K

 

[Fat Bastard]

While its on topic, I would just like to give an upfront warning that the following post is stupidly geeky.... but I suspect people will find it interesting.

Ultra High Gravity brewing is a commercially accepted way of making "light" beers with flavour profiles that are closer tho those of "normal'" beers. Something happens to the levels of total flavour compounds in worts that are brewed and fermented at over 16 plato (about 1.064). basically the percentages graph gets steeper all of a sudden. This means that you can make a beer - dilute it by half and still get 2/3rds - 3/4s of the flavour compounds that would have been in a full strength beer. Here's a graph to illustrate - note, numbers not real... just for illustration of the concept OK

UHG_brew..._profile.GIF

So you can see that a beer brewed at "normal" gravity with an OG of 9 plato (1.036ish) has significantly less flavour "stuff" than a beer of normal gravity (lets say 12.5 plato or 1.050) - BUT a beer brewed at 18plato and diluted to the same strength as the 9plato beer before packaging, has nearly as many flavour compounds as the "normal" beer does.

I can't for the life of me remember that actual numbers and I have exaggerated the steepness of the change to make it obvious - but its not that far out from what I remember was the real case. You could boost the TFC levels closer to the "normal" beer than to the low OG beer and win back more than half the flavour loss.

This was technique was once upon a time a Fosters trade secret - but everyone does it now. I'm wondering if there is a place for the technique in homebrewing?? Fosters doesn't really go above 18plato - efficiencies and other process realities start to make it not worth it... but it might be a way to make fantastic ordinary bitter or mild ale to have around in your keggerator.

Thirsty

So, digging up an old post here (as the fencing contractor said) but am I to take it that it is better to brew an over gravity beer and ferment it out before diluting back to a lower gravity?

I've got a cunning plan to make a high gravity Saison and dilute it back (either into the fermenter or into the keg) to get 2 Corny Kegs worth of 4.8% Saison. Obviously it would be better in terms of space to ferment one 25l fermenter's worth and dilute it back to 2 kegs than it is to use double the ferment space.

I'm not sure ive got a complete handle on the theoretical targets out of beersmith but I'm looking at an OG of 1.080 diluted back by half to 1.040. So a volume into the fermenter of 23.5l diluted back by the same amount of boiled and cooled water either pre or post ferentation.

Thoughts appreciated etc.

Cheers,

FB

 

[mckenry]

Hey FB,
As thirstys post implies, diluting back in the kegs can retain more flavour compounds. There are other concerns about high gravity brewing such as hop utilisation. Not too much of a worry with a saison though.
Youll just have to pitch the correct amount of healthy yeast to chomp through 1.080. Again, not a big problem with saison yeasts.
Definitely worth it for space saving.
Its a common method for those that have size limiting vessels. Yeah, beersmith can handle it. Theres a field that asks for top up water post fermentation or something like that. This will adjust the hop utilisation for you.

 

[technobabble66]

Yeah, TB's earlier post is fascinating.
There's some serious potential there for homebrewers.
It seems like the real trick mentioned in TB's post, aside from efficiency losses, is to fully deoxygenate the diluting water.
Not sure on the numbers involved but I'm assuming that'd involve a reasonable boil time.
I wonder if you could pre-fill your kegs with the required (boiled) water and sit it under CO2 & flush out the gas space a few times over a few days?
I guess it depends how deoxygenated the water that's been boiled for 30mins is, as to whether it's worth any extra steps.

 

[verysupple]

In terms of flavour, I think it depends what you want. Do you want half of a high gravity flavour profile or do you want a normal/low gravity profile.

I brew slightly over gravity because my kettle isn't big enough. I usually end up with ~20 L post-boil and dilute it to 23 - 25 L in the FV. I prefer to dilute it in the FV rather than at pakaging because the top up water is aerated and I figure you want that at the start of fermentation, not at packaging.

If I was going to brew double strength as FB has planned then I'm not sure how I'd do it - I'd need to carefully consider all the factors. But I do know one thing, if I was diluting post-fermentation then I'd want to be very sure the top up water was deoxygenated...and I'm not sure how I could do that.