# Astringency In Beer



## winkle (15/6/07)

I've got a batch of Pale Ale currently in secondary, that seems fairly astringent leading to a percived bitterness of about 10 IBUs higher than I'd like. Problem was probably caused by too hot sparge water (piss poor temp control). Since I don't particulary want to dump it I'm considering either:
a) brew a similar ale with lower IBUs (around half what was originally planned) then blend the two; or
b)cold condition in a keg for a couple of months.
c)tell myself to HTFU and pretend it supposed to be like that.

Anyone had success rescuing an astringent batch?


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## yeungnut (15/6/07)

How long did you sparge for? Did you take a gravity reading of your final runnings or taste it?

I've had problems with astringency and Pales before, as you mentioned probably relates to tannin extraction from the husks. If you acidify your sparge water this should help with your next batch. 

Its hard to enjoy the taste of an old teabag while drinking your beer. 

Cheers


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## winkle (15/6/07)

CILA Brews said:


> How long did you sparge for? Did you take a gravity reading of your final runnings or taste it?
> 
> I've had problems with astringency and Pales before, as you mentioned probably relates to tannin extraction from the husks. If you acidify your sparge water this should help with your next batch.
> 
> ...



I batch sparge, the first addition after mashing would have been close to boiling (SWMBO interuption) which I guess has leached enough tannins to effect the bitterness. Temp control will be fixed this weekend. I'll wait until fermentation has finished to see how bad it is.


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## Aussie Claret (15/6/07)

Winkle,
If you are batch sparging I don't believe that you would have extracted any harsh tannins with near boiling sparge water. I do this always and was instructed to do so, by our brisbane mentor.

The reasoning behind this as I understand is that the thermal mass of the grains will increase with near boiling sparge water but they would probably have only increased in temperature to about 80ish C.

I honestly think that the bitterness or astringency is probably from other factors. For example I have found that if I don't add Gypsum I can get harsh bitterness.

Hope your beer turns out ok. FWIW I don't think that ageing will have any effect on the astringency, perhaps the blending is a better way to go. Try mixing in a pint glass half / half before you blend in the kegs though, just incase this doesn't work and you end up with 2 kegs of astringent beer.

Cheers
AC


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## winkle (15/6/07)

Aussie Claret said:


> Winkle,
> If you are batch sparging I don't believe that you would have extracted any harsh tannins with near boiling sparge water. I do this always and was instructed to do so, by our brisbane mentor.
> 
> The reasoning behind this as I understand is that the thermal mass of the grains will increase with near boiling sparge water but they would probably have only increased in temperature to about 80ish C.
> ...



Good point, thanks. I'm sure I put the gypsum in, er pretty sure anyway.


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## Darren (15/6/07)

Percieved astringency can also be caused by using too much "harsh" hops


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## KoNG (15/6/07)

i brewed a 100% ahtanum blonde ale a year or so ago, which was a real biatch to drink in the first few weeks. The bottles got stored for several months and mellowed a bit, but were still not great. I would just blend with other maltier APA's from then on in, worked quite well. I also had a mate who seemed to enjoy it straight up, so he got a crate! haha


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## Ross (15/6/07)

winkle said:


> I've got a batch of Pale Ale currently in secondary, that seems fairly astringent leading to a percived bitterness of about 10 IBUs higher than I'd like. Problem was probably caused by too hot sparge water (piss poor temp control). Since I don't particulary want to dump it I'm considering either:
> a) brew a similar ale with lower IBUs (around half what was originally planned) then blend the two; or
> b)cold condition in a keg for a couple of months.
> c)tell myself to HTFU and pretend it supposed to be like that.
> ...



Winkle,

I'd waiting till it's settled & carbonated before being too critical - I've had some beers that have tasted similar to what you describe in secondary, but once they've been kegged have been fine. It's very easy to get some trub, or hops (if dry hopped) in your sample, which can have a real negative effect on the flavour.
I can't see it being from sparging, as previously mentioned by AC.
Add some polyclar to the secondary as well, this often helps remove astringency.
Worse case senario, put it on for the swap, we'll all be too pissed to notice  

cheers Ross


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## chris.taylor.98 (15/6/07)

Winkle,

I have used gelatin to help get rid of astringency with some success in the past.

Although I am not sure whether my "astringent" taste was just caused by flocculate grain particals down the bottom of the fermenter or actual tannins, as I am pretty paranoid about leaching tannins these days. 

( Don't sparge too warm, and make sure the mash stays below 5.6 ph even when doing my last batch sparge.
Also changed my lauder tun to have a finer filter on it. )

I have also stopped doing secondaries recently, so don't know if this would be the cause of the perceived astringency. 

Anyway seems to go away after cold conditioning for a couple of days then fining with the gelatin.


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## milpod (15/6/07)

Dude, what beer are u making?


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## chris.taylor.98 (15/6/07)

Why does this seem a bit odd? It's just a humble bock. Even tried a decoction mash this time, doesn't seem to have done much for it though.

Fortunately it gets another month or so to lager before I really have to admit how badly it turned out


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## kirem (15/6/07)

to remove excess tannin I would follow Ross's advice and use some PVPP. You can try other fining agents as well, egg white and skim milk are others that work on different sized tannins. I am a big fan of PVPP. Gelatin is a monster and I would consider it over kill.

Just be sure it is tannin before going down the fining path, it may just need some time to come 'round.

The best method would be to do a trial on 50mL samples and find a rate that you are happy with, as fining agents don't just take out tannin, over fining will make your beer characterless.

Kirk


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## Jye (15/6/07)

kirem said:


> to remove excess tannin I would follow Ross's advice and use some PVPP. You can try other fining agents as well, egg white and skim milk are others that work on different sized tannins. I am a big fan of PVPP. *Gelatin* is a monster and I would consider it over kill.
> 
> Just be sure it is tannin before going down the fining path, it may just need some time to come 'round.



Hey kirem, Ive been have a chill haze problem and resorted back to gelatine because it works, but I havent found any literature that states if it removes protein or polyphenols. Can you confirm if it removes one and if so which?

Cheers
Jye


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## newguy (16/6/07)

Jye said:


> Hey kirem, Ive been have a chill haze problem and resorted back to gelatine because it works, but I havent found any literature that states if it removes protein or polyphenols. Can you confirm if it removes one and if so which?



I've heard that the polyvinyl whatever finings will settle out tannins too, but I heard this from a winemaker. He said that his tannic wine lost its tannic character after using polyclar (I think it was polyclar). I don't use finings other than Irish moss, so I don't know if they do actually remove tannins.

From my own experience with tannins (I had issues with them for about 7 years, off and on), here are the things that I've found are important, in order of their importance.

- Water chemistry. I add about 2 - 3 ml of 88% lactic acid to my total volume of brewing water. Your water source's pH and hardness will dictate the amount of acid to add.
- Water temperature. It's okay to add boiling water to your mash tun, but be careful not to let the mixture exceed 75C/167F.
- Oversparging. Stop the runoff when the gravity drops to about 1.008.
- Grain crush. It's important that your mill doesn't pulverize the malt. Broken in two is all that's required.
- Hops. This is unavoidable with some hop varieties, and with heavily flavour & aroma hopped beers. However, it is quite easy to discern grain astringency from hop astringency.


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## Screwtop (16/6/07)

I fly sparge with water at 98 and the mashmaster thermometer in the grain bed usually drops to below mash out temp 76.5C something around 70 ish.


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## bonj (16/6/07)

Here's a link to a good article on beer hazes:

The Nature of Beer Hazes

Alot of it is over my head, but what I do understand makes sense.


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## warrenlw63 (16/6/07)

winkle said:


> I've got a batch of Pale Ale currently in secondary, that seems fairly astringent leading to a percived bitterness of about 10 IBUs higher than I'd like. Problem was probably caused by too hot sparge water (piss poor temp control). Since I don't particulary want to dump it I'm considering either:
> a) brew a similar ale with lower IBUs (around half what was originally planned) then blend the two; or
> b)cold condition in a keg for a couple of months.
> c)tell myself to HTFU and pretend it supposed to be like that.
> ...



Hey Winkle.

You said you're sampling it from the secondary? Sometimes It can be as simple as the beer's being tried way too cold (3 degrees or below). Usually causes the malt flavours to become somewhat muted and the hops to dominate leading to the perception of some astringency.

Did you try sitting a glass warm for a while and trying it at around 8-10 degrees? May tip the balance back. :unsure: 

Warren -


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## kirem (16/6/07)

Jye said:


> Hey kirem, Ive been have a chill haze problem and resorted back to gelatine because it works, but I havent found any literature that states if it removes protein or polyphenols. Can you confirm if it removes one and if so which?
> 
> Cheers
> Jye




Sorry for the long reply, but you asked

Some background info a lot of it is cut and paste. There really is a lot of information out there.

From
Handbook of Brewing
Food Science and Technology (Marcel Dekker, Inc.) ; 64
by Hardwick, William A. 

Although good clarity can be obtained from simple sedimentation, better results can be obtained in less time by using fining agents. Because of their chemical structure, they carry a net positive charge and interact with yeast cells, which are negatively charged, and with negatively charged proteins (Hough et al., 1982). Negatively charged proteins have been implicated in haze formation (Savage and Thompson, 1972). Consequently, removal of these compounds improves physical stability. Finings increase the volume of tank bottoms and also increase tank clean-up costs and beer losses. The most common fining agent is isinglass which is made by extracting collagen from swim bladders of certain fishes (Chapter 11). Other fining agents are tannic acid, silicates and silica gels, and clays (Coors, 1977)

And from
Brewing: Science and Practice
Woodhead Publishing in Food Science and Technology
by Briggs, D. E. 

15.3 Stabilization against non-biological haze
Competition between brewers is intense and the quality and consistency of their beers is
paramount. This demands that the beers following maturation should not only have
desirable, stable flavours but must also display stability with respect to haze, i.e., the
beers must be bright and remain so during the period from dispatch from the brewery to
drinking. Therefore, in addition to removing yeast, beers must have the precursor
constituents of haze removed to ensure long-term stability. Beer haze and its chemistry
are considered in Chapter 19. In this Chapter we focus on the removal of haze-forming
materials to ensure the production of a stable beer.
A range of substances can cause non-biological haze in beer:
Beta-glucans, which can often lead to hazes not easily seen by eye but which cause high
levels of light scattering in 90deg haze meters
Alpha-glucans (starch), which can behave similarly to B-glucans
pentosans, which may be derived from wheat based adjuncts
dead bacteria from malt
oxalate from calcium deficient worts.
However, the most common, important and troublesome type of non-biological haze is
that deriving from the cross-linking of proteins and polyphenols and it is the elimination
of the precursors of these polymers to which beer stabilization treatments are directed.
The most effective beer treatment with respect to haze stability is the cold storage of
the beer for about seven days at -1 to -2 degC (30-28 degF). This technique allows a
reduction in the cost of other beer treatments designed to remove potential haze-forming
proteins and polyphenols. However, brewers frequently wish to accelerate the process of
haze stabilization and achieve greater stability than is possible with cold storage alone.

15.3.1 Mechanisms for haze formation
Colloidal haze in beer arises from the formation of protein-polyphenol complexes during
beer storage (Gopal and Rehmanji, 2000, and Chapter 19). Fresh beer contains acidic
proteins and numerous polyphenols. These can come together by loose hydrogen bonding
but the associations formed are too small to be seen by the naked eye. These polyphenols,
called flavanoids, can further polymerize and oxidize to produce condensed polyphenols,
which have been called tannoids (Chapon, 1994). These tannoids can `bridge' by
hydrogen bonding across a number of proteins to form a reversible chill haze (Fig. 15.3).
This haze forms at around 0 degC (32 degF) but redissolves when the beer is warmed to 15 degC
(59 degF). After further storage of the beer strong bonds can form between the tannoids and
proteins and irreversible, permanent haze is formed. The rate at which this haze is formed
and its extent of formation depends on the raw materials used in wort preparation and the
process conditions. This `model' suggests that effective stabilization should be achieved
by removing from the beer the constituents of the haze, i.e., the `tannin sensitive' proteins
and/or the polyphenols.

and

http://www.brewrats.org/haze.html

Now I am not sure if the original question asked by Jye is a setup question or not, but as far as I know the reaction of gelatin (or isinglass both are really forms of collagen) is not entirely understood;

the following is from;
View attachment 13222


Isinglass Reaction Mechanism
The mechanism of isinglass fining is poorly understood. The long held mechanism
theory states that positively charged isinglass reacts with negatively charged yeast to
form a neutral floc which then precipitates. The role of auxiliary finings being to
interact with the positively charged protein particles which would otherwise not react
with the isinglass.
An alternative mechanism has been proposed where the soluble collagen reacts with a
soluble beer component to form a precipitate or floc. On formation, this floc surrounds
and enmeshes, and then binds to, the yeast and protein particles, and settles out of the
beer, sweeping up further particulate material on its way to the bottom of the vessel.
The role of auxiliary finings is to either react with positively charged soluble beer
components which would compete with isinglass, or to react directly with the isinglass
itself to produce the flocs required for fining.

In my day job I use the following

Use gelatin (never) to remove shorter chained young tannins/phenols - very aggressive. Use with vanilla and cream, makes a nice dessert.
Use casein or skim milk for moderate tannin reduction, removing medium length polyphenols, as well as some excess oakiness.
Use isinglass or egg whites to remove long chained, 'older' polyphenols/tannins, improving mouthfeel/astringency.

Although I don't have 'astringency' problems in beer land, I still take all my beers down to -2degC

Cheers

Kirk


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## Jye (16/6/07)

kirem said:


> An alternative mechanism has been proposed where the soluble collagen reacts with a
> soluble beer component to form a precipitate or floc. On formation, this floc surrounds
> and enmeshes, and then binds to, the yeast and protein particles, and settles out of the
> beer, sweeping up further particulate material on its way to the bottom of the vessel.




Thanks Kirk, this make sense in a 'hand wavy' way and seems to be how its working for me.




kirem said:


> The role of auxiliary finings is to either react with positively charged soluble beer
> components which would compete with isinglass, or to react directly with the isinglass
> itself to produce the flocs required for fining.



This is how I originally thought gelatin worked to remove protein in conjuction with another finning. The link Bonj provided has a nice pictorial explanation of this.


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## goatherder (16/6/07)

Thanks Bonj and kirem for posting those resources. I now have a much better understanding of haze and finings. Cheers.


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## Jye (16/6/07)

It been a big morning of learning and I have picked up a few minor changes to try next time I brew.

The biggest thing is how gelatine might work and is give in a great pictorial here on page three. This also show that gelatine increases the particle size to about 100um which increases the sedimentation velocity from 0.13m per day to 13m per day according to stokes law, meaning it will take less than a day for a keg to clear in theory. I have also been over fining and should only be using about 0.8g per keg.

This has been fun and I still have the Wort & Beer Clarification Manual to read


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## kirem (16/6/07)

Mate,

fining and balance in wine are really my bread and butter. Tannin chemistry was the biggest headache at Uni and is probably the most misunderstood and under-knowledged (is that a word) part of winemaking.

Most of it is the same in beer.

Glad you got something out of it. I wonder about making large technical posts on here (even if it is mainly cut and paste), but I figure most brewers want to know why.

If it makes better beer for you then I am glad.

Oh and the manual is the complete document of the one bonj posted.

Kirk


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