A Guide To All-grain Brewing In A Bag

[Hashie]

It is known that oxidation plays an important part in the formation of protein haze and that compounds known as melanoidins function as anti-oxidants and prevent the oxidation of protein. Oxidation also plays an important part in the production of colloidal haze, hence the name "oxidation haze", first coined by Helm, the German brewing scientist, in early part of this century.

Moreover, the formation of chill haze is also considerably increased by oxidation. Chill haze occurs in finished beer during cold storage, the chill haze will disappear if the beer is warmed (this is only viable if the beer is to be consumed immediately, if the beer is chilled again the haze will return). Later the beer will throw an irreversible haze at ordinary temperatures. Permanent haze is the end product of chill haze. If you get chill haze permanent haze will follow in time.

The oxidation of melanoidins will result in a lower quantity of stable colloids. Unstable colloids promote chill haze and permanent haze in beer. Conversely, the presence of stable colloids inhibits chill haze. The stability of beer colloids is the result of a very complex equilibrium, and the whole problem of colloidal haze formation is very complex. A better understanding of this problem will show it possible to take some steps to minimize its effects in finished beer.

Work done by Jean De Clerk, the famous Belgian brewing scientist has shown that darker beers are inherently more stable and clear. De Clerk attributed this to the presence of large amounts of melanoidins found in darker grains.

Melanoidins were first discovered by the French chemist Maillard, the reaction between amino acids and sugars which form these substances is know as the "Maillard reaction".

By definition, melanoidins are stable complexes formed at high temperatures (i.e. mash out temps.), they are colloidal in nature and are powerful reducing agents and give an acid reaction in aqueous solution. melanoidins are reddish-brown colored substances with a characteristic aroma (malt).

Color and aroma are not the only traits that melanoidins contribute to a beer. Their colloidal nature enables them to "protect" unstable colloids present in beer and to prevent haze formation. At the same time, melanoidins are powerful reducing agents and this too can prevent beer from throwing a haze. In addition the acid character of melanoidins helps improve the quality of beer.

You can read the full article here, Spills.

Edit; get the right quote!!

 

[Thirsty Boy]

I wouldnt take that as gospel. Firstly, evaporation is independent of batch volume. So any reference that specifies a maximum evaporation as a percentage, and doesnt specify the batch size, is inherently flawed. If I brewed an 8l batch, I would get 100% evaporation, and that would be exactly the right amount.

Secondly, not boiling hard enough can easily have a detrimental effect on your beer, while I havent seen much evidence that boiling too hard can. How do you get your wort "excessively hot" when it is at boiling point?

Best to achieve a vigorous rolling boil, so that you know all the required physical and chemical processes are occurring in your wort, and not get hung up on what the evap percentage is.

Sorry for the off topic, if you seacrh on evaporation loss you will find plenty of threads discussing these concepts.

Last time I looked, I didn't seem to be Jesus, so of course you shouldn't take what I say as Gospel..... that said, I respond thusly.

And He spaketh these words of wisdom.....

How is evaporation rate expressed as a percentage flawed?? You are of course correct, evap rate isn't dependent on batch size (in a given kettle, up to a point), it is dependent on heat applied and kettle geometry. But whats that got to do with expressing it as a % figure?

If you have a 30litre pre boil, and you shoot for a 15% (per hour) boil off rate you end up with 25.5 litres, if its 500litres you would boil off 15% for a final volume of 425 and for 8 litres (BTW I have actually brewed several 8 litre batches) at 15% you would try to boil off 1.2 litres for a final vol of 6.8.

So you ending up with 100% evaporation in an 8 litre boil, could only happen if you express your boil off as a litres per hour figure. Now thats fundamentally flawed if you dont include a batch size. 8 L/hr might be OK for a 40 litre boil, but it would be a ludicrously weak boil for a 500litre boil and obviously far to strong for an 8 litre boil.

Thats the whole point of the percentage figure - it doesn't actually specify a boil off amount, it specifies how vigorous the boil should be, regardless of batch size. A 15% boil will be more vigorous than a 5%, every time, no matter what the volume of the boil.

I regularly boil in 3 different sized kettles with batch sizes from 6 - 35 litres. I shoot for 12-15% and thats about the same amount of "vigour" in each case.

Now, I get that different people have different experiences, but, if you are looking at the majority of the brewing literature, the accepted wisdom is that a boil needs to be at least 8% per hour to do its various jobs, with most breweries going for something between 10 and 15%.

Too weak a boil will hurt your beer & too vigorous a boil can also hurt your beer, I'm not saying it will every time, but it definately can. I could put in a bunch of quotes and references, but suffice it to say that they exist.

So... the whole point of advising someone to shoot for a maximum of 15% is that they will then be in the safe zone. 15% is easily a vigorous enough boil, but means you wont experience the possible ill effects of a too vigorous boil.

Sure, an individual might not experience negative effects from boiling too hard, great !!! , their system, technique, styles brewed and flavour preferences mean that they can get away with something that could well be detrimental. Good for them. Its not what I'd call a fantastic thing to be advising a new AG brewer to be doing though.

Perhaps something along the lines of ---

"Hey, your boil off rate seems really high. Its way up around 30+% per hour! Thats a fair bit higher than the rate that would usually be reccomended. You could be doing your beer a bit of harm. A more conventional rate would be to aim for a nice rolling boil, but to try not to evaporate more than 15% per hour.
Of course, there are people who do boil at more than 15% and they dont have any trouble, so you might be okay. But to play it safe, maybe you should try to get it down to under 15%. Have fun"

--- would be a nice compromise between our two points of view


Anyway, end of sermon and down from my mountain.

Thirsty

PS... for a really good and user friendly type discussion about this topic (naturally enough one that supports my point of view ) Try the Kosch and Altbier episode of the Jamil show at about the 1 hour and 14 minute mark. Linky link

 

[T.D.]

Last time I looked, I didn't seem to be Jesus, so of course you shouldn't take what I say as Gospel..... that said, I respond thusly.

And He spaketh these words of wisdom.....

How is evaporation rate expressed as a percentage flawed?? You are of course correct, evap rate isn't dependent on batch size (in a given kettle, up to a point), it is dependent on heat applied and kettle geometry. But whats that got to do with expressing it as a % figure?

If you use the same sized vessel for different sized boil volumes, you will get almost identical boil off rates in LITRES. For me I get 5L of boil-off, regardless of whether its a 17L batch or a 30L batch. 5L out of a 22L boil is 23%, but 5L out of a 35L boil is 14%. That's why using percentages is flawed. If using percentages, a change in the batch size will automatically re-calculate the boil-off volume (in litres) as a different figure, when in reality it doesn't change.

 

[PistolPatch]

Hashie first, Jesus second

Hashie: You're a champion. Thanks for taking the time to post that. It's especially good when you weigh and crush your own grain then you can trust the figures a lot more. I've been getting mine from a local HBS here and I'm very unsure of their weighing ability :blink: Time I started cracking my own.

I'd love you to keep us posted on your efficiency on your next few brews and am really looking forward to hearing what you reckon about the effect of adding the spec grains in at mash out. Top stuff mate!

Jesus: That was another great read and the Jamil bit a great listen. I must say that I had never heard anything like that before. Interesting stuff eh? (For those that can't download 40MB, he was saying that a high evaporation rate can give you strong melanoidan flavours in altbiers etc and that you should aim at 12%. Don't ask me what melanoidan is!)

Until reading your post I had never considered the dilemmas of using small pots etc. I'd always viewed this subject from the normal batch size and more along the lines of surface area of your pot. The reason for me doing this was that maybe a year ago, before I knew anything about boils, I tried to do a slow boil to reduce the huge evaporation rate from my Robinox pot (diameter 45cm). I still seemed to be up around the 25-30% mark so I assumed that surface area was the important thing. I ended up reducing my boil from 90 to 60 minutes. BTW my boil is not what you would call 'spluttering.'

Obviously there is only so much you can slow your boil down to so I suppose kettle geometry (as in maybe leaving the lid on a little) might help here though if my memory serves me correctly, I don't think this made any difference either. Grrr. [Just saw TD's post and this shows what a limitation kettle shape makes I think.]

So for me, I think reducing the evaporation rate is quite a hard thing to achieve. I'll have access to a second set of BIAB equip soon so will have to have another look at this.

Jamil's thing about just making sure that the wort is circulating in the boil was very interesting though. Mind you, like everything in craft-brewing, you'll read the opposite somewhere else!!!

Anyway Jesus, a very educational post as always.

Lots of love,
Thomas

P.S. I imagine that getting the evaporation rate exactly right is something for new AG'ers not to obsessively worry about. As Jamil said he boiled like buggery for years. In reality it's probably more of an advanced topic for those wishing to brew a beer to perfection. Consistency of the boil should probably be the first goal. Very interesting stuff though and I'm enjoying the education :super:

 

[apd]

If you have a 30litre pre boil, and you shoot for a 15% (per hour) boil off rate you end up with 25.5 litres, if its 500litres you would boil off 15% for a final volume of 425 and for 8 litres (BTW I have actually brewed several 8 litre batches) at 15% you would try to boil off 1.2 litres for a final vol of 6.8.

...

Thats the whole point of the percentage figure - it doesn't actually specify a boil off amount, it specifies how vigorous the boil should be, regardless of batch size. A 15% boil will be more vigorous than a 5%, every time, no matter what the volume of the boil.

Thirsty,

I was in TD's and Guest Lurker's camp before. I always thought that the evaporation was related to surface area so whether or not you had 30L or 10L in the kettle, if you boiled it for 60 minutes, you'd lose the same volume from both. But you've got me thinking and I think I'm missing part of your argument.

If I understand you correctly, what you're saying is that you boil to a specific amount, ie. you start with X litres in the kettle and know that you need Y litres at the end of the boil and therefore you boil until you have Y left, meaning your boil length is variable depending on your boil volume. Is that correct?

The problem I have is that I assume that the time it takes 8L to boil down to 6.8L is a lot less than the time it takes 30L to boil down to 25.5L (as per your figures above). With that in mind, how do you fit in hop additions? For example, if it only takes 30 minutes for 8L to boil down to 6.8L, how do you get a 60 minute hop addition? I've just picked 30 minutes out of thin air. I've never actually boiled 8L to see how long it takes to reduce in volume. I know I'm missing something so hopefully you can fill in the missing part of the puzzle.

Thanks,

Andrew

 

[3GumsBrewing]

Anyway, end of sermon and down from my mountain.

Thirsty

PS... for a really good and user friendly type discussion about this topic (naturally enough one that supports my point of view ) Try the Kosch and Altbier episode of the Jamil show at about the 1 hour and 14 minute mark. Linky link

Thanks again Thirsty and PP,

I did another Belgian Pale yesterday - same ingredients, same mash and boil times, except I made sure the boil was not as vigorous/rapid, but still rolling. (love my 4 ring burner).
Started with 32L, ended after 60min with 26L. Much better I think.

Also re-listened to that podcast, good stuff. Jamil is great isnt he! Almost tempted to not use secondarys like he does (just can't bring myself to do it though!)

Cheers
DK

 

[T.D.]

If I understand you correctly, what you're saying is that you boil to a specific amount, ie. you start with X litres in the kettle and know that you need Y litres at the end of the boil and therefore you boil until you have Y left, meaning your boil length is variable depending on your boil volume. Is that correct?

Regardless of my boil size (within reason) a 60min boil gives me a boil-off loss of 5L. The boil length is held constant.

 

[SpillsMostOfIt]

The Thirsty Messiah has three kettles. If he boils the same volume in each of them, he will boil off different volumes because the kettles are different. He will be aiming for the same boil-off as expressed as a percentage, because that is how he measures the anger of his boil.

I have just one kettle. If I boil three different volumes in it, I will get the same volume boiled off, which when expressed as a percentage of the original volume will be different.

He's not the Thirsty Messiah - He's just a very naughty brewer...

 

[Thirsty Boy]

You can also... and I know this might be a revelation, turn your heat up and down.

Saying that you boil off X litres per hour regardless of batch size is fine, of course it works and is consistent. When you express it as a %, it doesn't give you a changed and therefore flawed figure, it gives you a changed figure and you are supposed to actually change[u/] your pot, set-up, flame etc to alter the sitation so that you boil off the new volume, thats the whole damn point.

apd - nearly what I meant, but not quite. You should aim for a nice rolling boil, doesn't have to be fizzing and jumping around, just rolling over at a reasonable pace. Once you have done a few brews, work out roughly what your rate of boil off is, if its more than about 15% I suggest you want to turn the flame down a bit, or if that would reduce the vigour of your boil too much, then maybe partially cover the opening of your pot, or in an extreme case, you might be better served with a smaller pot

Now you probably brew reasonably consistent batch sizes, so you can fairly easily convert a % figure to a L/hr figure and thats easier to work with. And if you are going from a 25 to a 30 litre boil, bugger it, you will be near enough, no need to recalculate. Just use the litres per hour figure. But if you want to brew a 10 litre batch or a 40 litre batch, well then you need to try and re-calculate for the new volume.

The reason is that even though in the same pot,the l/hr figure will remain constant, the actual vigour of the boil will change with increasing/decreasing volume. and you want it to be where you planned it to be, not just where it ended up.

You aren't boiling to a specific volume per say - you are boiling at a specific level of vigour/anger/intensity for a specific time. You then work out the volumes you need from that.

Like I said, if you are mainly brewing the same batch size, it wont really matter to you, just go with a litres/hour figure. I just recommend that the litres/hour figure turns out to be less than or equal to 15% (per hour) of your starting boil volume. If you are boiling off heaps faster, you just turn down the heat a bit.

But what the hell, other people think it doesn't matter. Maybe they are right.

You're all individuals

Thirsty

 

[SpillsMostOfIt]

My goal is to have a totally standardised brew process, meaning that I know that when I use this much water, this much grain and boil for this long (usually 90mins), I will get a magic number of litres (24) at the end.

I've given up trying to measure the volume of water that goes in - I just measure by depth in my imperfectly-cylindrical pot. I haven't worked out my evaporation rate - I just know that as long as I make the appropriate adjustment for the amount of grain I'm using and turn both elements on for the duration, I end up with a plastic jerry full (and not much more). That's all I need, I think...

This thread has made me wonder again if I might be scorching my wort, so I might just have to use this as an excuse to brew again soon...

I think that if it works as a repeatable, mechanical process, the other stuff might not matter that much, but then, I am not an individual.

 

[apd]

Thanks Thirsty. Good info.

Andrew

 

[PistolPatch]

Thirsty, it's Thomas again

One of the interesting things in that podcast was that Jamil said he could taste the difference on a brew that was done at 12% versus 15% evaporation rate. I don't think too many of us would be able to taste that sort of difference but it would be nice to get down from the 25-30% I get in my pot! You've inpsired me to have a crack on the weekend.

One of the best things about BIAB I think is the ability to do side by side brews for still minimal cost. I'm about to get a second set of equipment which means another kettle and burner. Times this by two and it is still less in cost than most traditional set-ups but it gives you...

The Ability to Side by Side Brew on Your Own

This ability is a massive advantage. How many brewers do you know that have the ability to do a side by side brew? Not only can you brew twice the amount of either the same or a different beer but you can change brewing factors and see for yourself if you notice a difference.

For example, you could try doing the same brew with 2 highly different evaporation rates to see if it is significant for that particular beer.

The possibilities here are endless and the learning curve truly brilliant as unless you brew a beer on the same day, you can never really taste them side by side as one will be a day or week older etc.

I can't wait to start doing this.

Anyway, I scored 30m of copper today for free so I'm going to go and braze me up a new immersion chiller - cool!

Cheers,
Pat

Pat's Tip for The Day: If you want to make an immersion chiller like mine (slightly conical,) to shape it, buy a plastic garden pot from Bunnings and then return it the next day

 

[bayWeiss]

PP,

I have never done BIAB, can you please explain exactly how BIAB gives you an advantage in doing a side-by-side brew as opposed to batch or fly sparge? I read your post a couple of times, but I am still missing it.

I have split a batch before, with traditional sparge techniques, and did not think that it could get easier!

thanks!

:beer:

 

[PistolPatch]

Mornin' Bayweiss,

The advantage of side by side brewing with BIAB is mainly cost and practicality (time and space).

Let's say that you wanted to brew the same beer at different evaporation rates to see the difference. For real side by side brewing, I think that simultaneous brews are going to give you the most accurate results. (For example, even your tap water can change in composition from one day to the next - even one hour.)

To do this test with traditional equipment, you'll need 2 HLTs, 2 Mash Tuns, Two Kettles and 4 Burners. You'll also need room to put all this and high concentration levels!!!

With BIAB, you need two kettles, 2 bags and 2 burners. (I haven't mentioned chillers in either of the above but you get the picture.)

The second option is of course far cheaper and doesn't require as much space or concentration. If you had all the BIAB equipment to side by side, you could also try batch-sparging if you had an esky lying around - just put your bag in the esky. So there are a lot of advantages here.

(And even, if you are not side by side testing, let's not forget the huge advantage of being able to do two totally different brews in pretty much the same amount of time.)

I think, because we are human, we often change one thing in a brew and assume that after just that one brew that the change worked or didn't work. The scientist in us though knows that it is very hard to brew exactly the same beer next week as you do this week. Unless you were highly educated in tasting and taking notes, it is almost impossible to taste Beer 1 today and then taste Beer 2 a week later and compare them. Your taste buds might be working totally differently from one day to the next.

Side by side brewing gives you far more accurate information (assuming you do it correctly) as you can brew the beer at the same time and taste it at whatever age at the same time.

I'm not totally sure what you mean when you say you have split a batch before but I assume that you did the split after the boil? This means you can't try variations on things before the boil such as mash temps, evaporation rates or hop additons. You are limited to just testing things like different yeasts or fermentation temps.

Even if you split it straight after the mash and did two separate boils, you are still unable to test mash variations and unless you have two kettles and do the boil simultaneously, the second wort is going to be sitting around for a few hours waiting to get boiled which leaves further room for variance.

I hope that clears that up mate. Certainly kept me from going and doing some work.


Pat

 

[lucas]

Let's say that you wanted to brew the same beer at different evaporation rates to see the difference. For real side by side brewing, I think that simultaneous brews are going to give you the most accurate results. (For example, even your tap water can change in composition from one day to the next - even one hour.)

To do this test with traditional equipment, you'll need 2 HLTs, 2 Mash Tuns, Two Kettles and 4 Burners. You'll also need room to put all this and high concentration levels!!!

actually PP, if you wanted to see the difference in evaporation rate thats not at all what you'd want to do, you'd be adding too many variables. how are you going to keep the HLTs at the exactly the same temp? how are you going to ensure identical mashes?

those arent problems that BIAB is magically going to solve. if you want to compare evaporation, then you need to mash a big batch of beer in a single tun, run it off into one vessel and mix it well, then split it for the boil, perhaps using your hlt as your second boiler. the earlier in the process you want to compare things, the more uncontrolled variables you introduce and the less likely it is you're going to be able to try perceived changes to any one thing

trying to do two batch from start to finish side by side is not going to give you any sense of the difference that your "one" change makes; in fact i'd bet that if you tried to do two complete batches side by side without ANY change you'd still end up with two slightly different beers

there's nothing wrong with BIAB as a process, but the evangelism is starting to get a little stale

 

[Kingy]

sorry to interupt but would a 50 litre or an 80 litre pot be better for BIAB

is an 80 litre big enough to do double batches and is an 80 litre to big and awkward to do a single batch?
im looking at the robinox brand.
and cant decide.

what do other BIAB'ers use and are they happy with what they use and what size would they change to if they were to change.

cheers kingy

im steering towards the 80litre but i dont know why........

 

[Maxt]

I have an 80L kettle, a few points..

Unless you have a mechanical system and a super strong bag, double batches are very iffy (it's hard enough to pull 6kg of wet grain out).

If you ever want to use immersion elements in the kettle in the future, 80L does not leave much depth unless you have a volume over 40L. You need to keep a certain amount of liquid over the element, and 30L barely covers it..but not an issue if you BIAB and use gas..but just a consideration for the future.

 

[PistolPatch]

Well bugger me on the evangelism comment!

actually PP, if you wanted to see the difference in evaporation rate thats not at all what you'd want to do, you'd be adding too many variables. how are you going to keep the HLTs at the exactly the same temp? how are you going to ensure identical mashes?

I didn't say that's all you'd have to do.

those arent problems that BIAB is magically going to solve. if you want to compare evaporation, then you need to mash a big batch of beer in a single tun, run it off into one vessel and mix it well, then split it for the boil, perhaps using your hlt as your second boiler. the earlier in the process you want to compare things, the more uncontrolled variables you introduce and the less likely it is you're going to be able to try perceived changes to any one thing

BIAB solves a lot of these problems - pure and simple. You haven't read my post. It depends on what you are testing as to what lengths you have to go to. It's not hard to brew the same beer and have one with a mild boil and one with a vigorous boil - not hard at all.

trying to do two batch from start to finish side by side is not going to give you any sense of the difference that your "one" change makes; in fact i'd bet that if you tried to do two complete batches side by side without ANY change you'd still end up with two slightly different beers

Wrong again. Brad_g and I managed to produce two identical beers - one BIAB and one batched. As I've said before, only one person could pick any difference and it was miniscule. I think that most people into this thread are not really interested in identifying miniscule changes.

there's nothing wrong with BIAB as a process, but the evangelism is starting to get a little stale

Where's the evangelism? Most of BIAB is restricted to this thread. I can't believe that you have a problem with myself and others putting so much time and effort into encouraging people to move into and learn about AG in a logical and easy manner. Most of the time I enjoy doing this but on days when I see inaccurate, ill-considered and berating posts, my enjoyment evaporates and then I start writing ill-considered posts :blink:

It's not your usual form Lucas - you usually post well. When I see at least one good reason why BIAB is not the most sensible and logical way for the overwhelming majority to begin making all-grain beer then I'll STFU. When I can see consistently better beers being brewed with another method then I'll start encouraging people to start with BIAB and move onto whatever that method may be. For the moment, there is not one reason to do either of the above.

That last comment of yours has no value to anyone apart from those who wish to illogically justify their method of brewing.

And finally, remember that I didn't just start this guide to BIAB, I also did the Guide to Mashing and Batch-Sparging. I'm interested in all ways of brewing not just BIAB. I write about BIAB more because of reasons that should be totally obvious.

It would be nice if more people directed those considering starting AG to this thread. I often see people just waiting until they have all the gear needed for traditional brewing whereas they could be under way immediately. Most of these people wouldn't even know what BIAB is.

Brewing is a fascinating world and most brewers love exploring things or seeing others take up the hobby. This is why BIAB has been helped by so many of the really experienced brewers.

Good on em! :beerbang:

Anyway I'm doing 3 brews this weekend so I'm going. I better not have a drink while doing them otherwise this keyboard will end up getting a hammering

 

[PistolPatch]

sorry to interupt but would a 50 litre or an 80 litre pot be better for BIAB

is an 80 litre big enough to do double batches and is an 80 litre to big and awkward to do a single batch?
im looking at the robinox brand.
and cant decide.

what do other BIAB'ers use and are they happy with what they use and what size would they change to if they were to change.

cheers kingy

im steering towards the 80litre but i dont know why........

Howdy Kingy!

I'd go the larger pot mate. There's no worries about boil-overs then on your normal batch-size. You can also use the larger pot as a 'fermenting fridge'. Just chuck your fermenter in it and wrap a thick camping mat around it. (Cut slots for the handles and it holds itself on nicely).

I have the 70lt and am thinking about getting another the same size. It's big enough to do a double-batch* but you'd have to watch it for boil-overs. As Maxt said, you'd want bloody good stitching etc to do double-batches. Alternatively, you could get a cheap, thin pot that slides into the larger pot, drill some holes in the bottom and line this with the bag material. You'd still want a pulley system though to lift it out.

*The only reason I'll be doing double-batches is because my brother-in-law and nephew want to get into the brewing. I'm thinking we can brew together and split the batches. When you're starting out, you are probably better off doing normal batch-sizes and trying a few different styles until you find your favourites. Maybe then is the time to look at the doubles. As mentioned though, the 80 litre will do 'em.

Looking forward to having a beer with you next time I'm up the mountains.

Spot ya
Pat

 

[Kingy]

Thx for the help pp and maxt

yea 80 litre is definately the go and just ordered,im one more step closer to BIAB

Double batches arnt something im thinking of doing soon, was thinking long term on other uses for the 80 litre. Dont want to buy a 50 then realise an 80 litre wouldve been better.or vice versa.

Hopefully within the next month i can get my shed stinking of boiled grain for some aromatherapy