BIABrewer.info

[Mods, I've started this thread here rather than clutter up the 'my first post' thread.]
Invariably questions about stovetop batch size and brewlength come up. Here's one recent question to start the ball rolling.
CShenk asks:

Yep CSchenk, as hashie relates, the cheap and plentiful 19L stockpot is my main weapon and Maxi-BIAB is the way I get bigger batches out of it (not sure if that's what you're after though?). The method has a few sneaky clever tricks which makes life a bit easier as well, so I do recommend it, but maybe try Mini-BIAB first to get a more wholesome BIAB experience, if you do that you should be able to get 13 or 14L per batch in that stockpot.
Now, with Maxi-BIAB you should be able to brew 23- 25L batches with relative ease, I do that pretty much all of the time, I've not done more than 25L but I don't have too many doubts about being able to do 30L of lower- strength beer (say around 3- 4% abv). The main reason I haven't done the bigger run is that I don't actually have a fermenter big enough, so it is pointless really unless I had a use for an extra 5L of wort (haven't until now).
Post- boil dilution is where the extra volume is made up, because we're adding just plain water obviously the wort (unfermented beer) is stronger than usual, but this doesn't cause any real problems and it is just a straight concentration- volume conversion. I usually mash 4.0 to 4.5kg of grain per batch, it generally yields 17L of about 1.070, so with a target gravity of 1.048, the maths go like this:
Actual SG / Target SG * Actual Volume , so 70 / 48 * 17L = 24.8L diluted, so the water added is 24.8 - 17 = 7.8L

As an aside, that example was a very efficient mash from 4.0kg base malt, 0.17kg specialty malt and 0.2kg dextrose, the dex is to style in a UK Bitter but brewing dextrose/ sugar- friendly styles is another helpful way to ensure volume and gravity targets are met. Also the sophisticated ( ) method that I use for filtering the wort (a simple kitchen sieve! ) is about as efficient as it can get, so just about all of that 17L of concentrated wort is captured in the fermenter, this also helps keep overall efficiency high and the desired batch size achievable.

Great topic Ralph.

This would probably be quite time-consuming/annoying for you but would it be possible for you to copy and then modify say this post to suit Mini and also Maxi-BIAB based on a 19 L pot?

I know you can't give exact figures but I think you have the experience to probably give some good averages from which new brewers could start from.

If you do think this is possible, I am happy to help with this in any way I can so please PM/post your thoughts. Having the Mini and Maxi-BIAB figures laid out in easy to read rows would be a huge asset to much of the brewing community and BIABrewer.info. Having a base gives these brewers a ball-park to work and talk from.

Giving new brewers a specific recipe, quantities and instructions to work with is a God-send to them. They don't have to be perfect, just a confident place to start.

Can you do this? Can I help?

Thanks Ralph this is very helpful. I really like the idea of the Maxi-BIAB idea. Right now I'm tracking down some voile to make my bag. Once I get the bag squared away I'm going to start a batch. I do have a question about the pictures you posted for the Maxi-BIAB. Do you ever have issues with hot break? That stock pot looked awful full after adding the first sparge. Do you not have issues with boil overs, or are you a champion stirrer? I haven't had a boil over yet and I really want to keep it that way, haha.

Others have said to have a spray bottle with water handy to "control" boilovers . . . or 200ml of water added just before eruption

Cheers
Bruce

I just wanted to tag onto this topic that I want to try BIAB but I want to make really small batch sizes. I want a brew length of 5 litres. Does anyone see any problems with making BIAB for batch sizes that small?

Hi there potatoes and welcome to the forum .

I can't see any problems with a batch-size that small. Just scale down the instructions in, A Guide to Mini-BIAB and ask any questions that aren't clear.

Your first few batches might not turn out to exact gravity or volume expectations but should still give you very nice beer. Once you have two or three brews under your belt, you will get very close. So on the first few brews, plan and think ahead as to how and when you can take some measurements...

I would take a pre-boil one and then cool it. Once cooled and measured, return it to the boil.

A good hydrometer jar will often take over 200 mls to get a gravity reading and this might cause you some problems with further gravity readings so consider the following...

Take a post-boil gravity reading. Sanitise a coffee mug and dip it into the wort at the end of the boil (while the wort is still circulating), cover the mug in plastic wrap, put it in the freezer for say 20 - 30 mins (until it 'feels' slightly cool, say 20 C) and then pour it into your hydrometer tube. Take your post-boil reading which will be your original gravity.

Then, if you are using dried yeast, sprinkle 4 or 5 grains into the tube at the same time as you pitch your main yeast and then cover your entire hydrometer tube (hydrometer still in it) with something that will stop 'nasties' falling into the tube. Maybe use a large cut-off soft drink bottle with the neck cut off?

Keep your covered hydrometer tube in the same place as your fermenter and you will be able to watch the fermentation progress and tell when it has finished without taking further readings and wasting more wort.

The above is a great practice even in larger batch size BIABs but it will only work with a decent hydromer tube. Most tubes that come with your hydrometer are way too thin to even get good OG readings. Using such tubes in the manner I have mentioned above would be useless as the krausen etc will stop the tube moving.

Sorry about the long post but doing the above is a very efficient way of monitoring your fermentation - much better than watching an air-lock!

Will look forward to your results potatoes
PP

Another thing to keep in mind is that smaller batches will lose heat quicker during the mash. There is a much smaller thermal mass so you'll want to consider using insulation of some kind.

A common practice is to wrap your kettle with towels, sleeping bag, or coat. This works best if you "pre-heat" the insulation; basically wrap the insulation around the kettle as you're heating the water to strike temp.

But as PP said, there shouldn't be any problems. Using The Calculator is a great way to scale your recipes.

Hi PP and BBH,

Thanks for the feedback. I am going to try the American pale ale recipe on the forum. I never thought about the loss from taking gravity readings. So PP I will give your idea a go and let you know how I get on.

In regards to keeping it warm I am caught between two ideas. One is that I insulate as other have done with jumpers and towels as you suggest. The other idea was to set the oven to 70 and put the kettle in there for an hour. As my batch kettle will be pretty small it should fit and sounds like an easy way to guarantee temp control. Does that sound reasonable?

Thanks again. Will let people know how the Micro BIAB goes...

Potatoes

Good point about using the oven. Should work fine.

Hi,

I tried the Micro BiaB in the weekend and it was fun trying a new way to brew. I ran into two problems. Firstly the Oven didnt work that well. The temp had dropped to 60c at end of the mash. Secondly, my kettle holds exactly 11 litres of water. When I heated 10 litres of water, there wasnt much room left and needed to remove some water before adding the grain. Apart from this it a good brew day and hopefully the beer tastes good too.

Thanks for your help, PP and BBH

Good to hear potatoes...I'm glad you enjoyed it.

I'm a little surprised the oven didn't work very well. I wonder if your oven wasn't actually 70C, did you use a thermometer to measure the actual temp? 70C is usually at the low end of what an oven can achieve (mine is "warm", don't know the temp, then 200 F) so your oven may not be able to regulate at 70.

I didnt actually test the oven with a thermometer. I just set it to 70. The temp gauage on my oven goes from 60 to 250c but, as you say, I dont think ovens are designed to be at a constant 70 temp. I might have a little play around with it and see what I can work out. Cheers, P

Just did my second BIAB. This time the Oven worked a treat. Mash went in at 65c and stayed exactly 65c every time I gave it an occasional stir. I think that last time I was just checking on it too much. With Two mini BIABs under my belt, it might be time to move to a Maxi-Biab. Its a lot of work to make 5 litres of beer.

Nice Potatoes!

I'm glad to hear that the oven worked out. I just got grains so I'm planning on trying the same thing. It's encouraging to hear that someone else had success with this technique.

Congratulations potatoes!
Yeah, just leave the mash alone is my advice, regular stirring just loses heat and has precious little other benefit. IMO.
If the oven is too fiddly to get right every time, rest assured the thorough lagging method does work quite well. I use a jumper and a coat, usually lose around half a degC, which is fine. Preheating the surface where the pot will rest, first placing some insulation under it and preheating the lagging as well will all help, I just overshoot the strike water temperature and allow it to come back to where I want it through heat loss in preheating everything else.
You're quite right about the amount of effort required per unit volume of beer, that's precisely the reason the Maxi variant was developed!

Hi everyone,

I have the 19 L pot setup, using a fine grade cheese cloth as the bag (not sewed). I did my first BIAB with it a couple days ago. The aim was to make 15 L of beer. I had a 3.2 kg grain bill, mashed in at 68 C, finished mash at 61 C after 90 min (forgot to mash out at 80 C). I kept adding boiling water to the pot during the boil to keep the volume up. The cooled wort after boiling just before putting it into the fermenter had an SG of 1.043 (is this reasonable?).

Looking at "The calculator" it seems ridiculous to have a 19 L pot only to have the BREW LENGTH of 9 L. Am I stretching the system too far by wanting to brew 15 L batches with this setup?

Any thoughts would be great.

Cheers,

Hi Schober, well done on your first BIAB! That sounds quite reasonable to me and don't worry too much about skipping the mashout. Cheesecloth may not last more than a few batches, but it is an adequate stop gap so long as it drains adequately, but polyester fabric will last considerably longer. Adding water to the boil is acceptable to keep the volume up, but bear in mind it will only reduce the OG/ dilute the wort, it could be that the grain may not have been completely drained?
WRT the piddly brewlength with Mini-BIAB in a 19L kettle, that's pretty much the prime motivator for Maxi-BIAB. I do 23 and 25L batches routinely by this method, however I recommend novice all- grain brewers do try Mini-BIAB first, just to get familiar with the BIAB concept and iron out any issues before stepping it up to a slightly more complex process.

Thanks Ralph,

I've read from the free howtobrew info that about 2.5 L/kg is a reasonable liquor to grain load. So that theoretically I could do this brew in 8 liters and sparge with another 8 liters. I would rather not get a larger pot because my electric stove may not handle it.

Why is it so necessary to add ALL the water at the start of the WHOLE process and boil down, rather than using the 2.5 L/kg figure for the mash and adding water to obtain a certain gravity?

Cheers,
Schobes

Hopefully I'm understanding you correctly and not going off topic...



It certainly isn't necessary, but it's the beauty of BIAB. What you're asking about (mash with half the liquor then top up with water) is essentially "no-sparge" brewing, not the same as BIAB (full-volume, "passive" sparge method). It's commonly stated that no-sparge gives lower efficiency. You have half the water to "rinse" the sugar from your grain then if you have a full-volume mash. Because of this, you'll need more grain to obtain a certain gravity and volume. So while it isn't necessary to add ALL the water at the start of the WHOLE process, it makes for higher efficiency and fewer steps in the brew day. But if this doesn't fit your equipment (i.e., too small of a pot for achieving the batch size you want), then I don't see a problem with mashing with half the liquor then topping up with water to meet your desired pre-boil volume and gravity. Then again, if you're that set on achieving this certain batch size, then I would definitely recommend Maxi-BIAB as Ralph has said.

Good Day, I found if you figure the grain bill needed to get a final volume of beer to a desired Gravtiy, you will never need to ADD water, the calculated boil off rate will get the Gravity correct, so "full volume BIAB" only needs the water added once at the start of brewing, and it gets lost in grain, Trub, Steam, and the occasional spill!

Thanks guys,

I really appreciate the advice from experienced BIABers.

Cheers,

This is why Maxi-BIAB is a Variation on stock/ full- volume/ 'pure' BIAB- it departs from the commonly recognised BIAB theory and processes. It actually uses similar L:G ratios to traditional methods and is more like a BIAB adaptation of a 3- vessel process. However, that wasn't the motivation to develop the method, no, the main reason I pursued development was that, a) I was tired of the smaller Mini-BIAB batches and wanted a 23L brew length, b) didn't really want to have to equip a couple of kegs (even though I have them on hand), and c) already had a 19L stockpot.
Maxi-BIAB has also developed into a low- risk method for novices to try a full- sized (i.e. 23L) all- grain batch without much in the way of additional equipment (just a sparge bucket). Mini-BIAB is a low- risk all- grain entry point, but the limitation is the brew length, however it is still the stock/ full- volume/ 'pure' BIAB which the pioneers would recognise and the one which we have all come to know and love.

Good Day Ralph, If you have followed some of the U.S. forums, many are going BIAB, and your ideas of merging sparge with full volume mash, may seem odd to some. Here in the States it is a great way to bring us, Yankees on board. You may have seen more people from the U.S. joining this site, almost all forums have this HTTP posted. Thanks

Hi joshua,
Yes, I've noticed the US forums (and magazines) seem to be embracing BIAB, or at least not as hostile as they were, same goes for the UK and mainland Europe I feel. There's a few members though that have been doing BIAB of one kind or another for a very long time (I'm no BIAB pioneer), but it was seen as a bit of a radical backwater and didn't get much traction. Nowadays I think things a different, BIAB has become mainstream.
I'm not fussy though, sparged or unsparged (i.e. full volume BIAB), so long as there's sheet of voile in there being lifted and no silly manifold present, its fine sweet by me!