BIABacus

Just a quickie regarding what to enter into the sheet:

Section L - Mash Volume should this be the water added to the mash tun or the total including grain?

If it includes grain then it seems you would have to wait some for the grain to absorb water?

[edit:] I am currently using Brewing Classic Styles for my recipes, I understand they work on a malt yield of 70% whereas the BIABacus uses an extract potential of 80%. I am assuming the wording points to the same thing but what about the numbers does this affect things? I guess my question relates to the fact I seem to consistently fall below expected OG and I am wondering after 3 brews whether this is my system or maybe this has something to do with it?

Finally (this post is not as quick as I thought ) I realise there are three formulas for in use for calculating IBU of a recipe and that they all give different results for the same inputs...therefore I was wondering how hard it would be to have the choice of which formula to use in the BIABacus. Probably too hard...but I was thinking that if you take the BCS book for example they use Rager, as I dont know what these recipes are supposed to taste like before I brew them, I am therefore not sure whether the outcome for IBU is right or wrong and to what extent it might be affected by the fact the BIABacus uses Tinseth rather than Rager? If you follow the question.

cheers

• • Quote
• • • 0
    • 0
    • 0
    • 0
    • 0

• • SVA Brewer With Over 100 Brews From United States of America
  • Quote
• • • 0
    • 0
    • 0
    • 0
    • 0

• • Quote
• • • 0
    • 0
    • 0
    • 0
    • 0

Okay. That unit is bigger than I thought.

• • SVA Brewer With Over 100 Brews From United States of America
  • Quote
• • • 0
    • 0
    • 0
    • 0
    • 0

Nice answers above guys .

Mash Volume, as balli state is the volume of your mash. That means the voloume in your kettle after you have added all your grains and strike water. It only take a minute for things to settle down but that volume figure can be measured any time after you mash in right through to just before you pull the bag.

The volume that is displaced by the grain is a totally different number from the volume that is absorbed by the grain. It is a tricky area and it has been answered several times but I'm not sure how you would find those answers. Hold on!... Search for 'displacement'. I'm pretty sure that will give something. Report back!!!!

IBU Stuff

Thanks to MS for giving you the link to the Brewing Classic Styles stuff.

I could write a book on that question but here's a few quick points...

a) Rager and Gartex have some totally dodgy assumptioins in ther ir formulas. For example, in one of them, if your wort is over 1.050 gravity then it will be totally differnt than if your wort was at 1.049 gravity. It is that ridiculous.

b) Tinseth is regarded as most accurate but it is still very primitive.

c) Brewing Classic Styles should have been published with a hop schedule for if you were brewing the recipe as an extract or if you were brewing it as an all-grain.

In the post that MS linked above I'm pretty sure, I surmised about why an all-grain brew would need more hops than an extract brew. All pretty logical stuff. Bugger me, if just last week I listened to a podcast with John and Jamil saying the same thing!

So, someone needs to ask them, "If all-grain brews need more hops than extract brews, how should we all-grainers adjust the hop schedules in, "Brewing Classic Styles?" It's a good question, I hope they wouldn't mind anyone asking it* and they'd probably agree with my answer.


PP

* These guys are generally very good at letting others know when they find new information - nice! It would be great to see a general correction sent out regarding the hop schedules in BCS.

• • SVA Brewer With Over 100 Brews From Australia
  • Quote
• • • 0
    • 0
    • 0
    • 0
    • 0

• • Quote
• • • 0
    • 0
    • 0
    • 0
    • 0

HM, now I'm feeling really bad about that acknowledgement post I wrote the other day . Please don't worry about doing a long reply here or anywhere else (unless you need or want to). I'm really happy with a quick post saying whether anything I wrote made sense or how drunk you reckon I was when I wrote the post .

So, if there is no need to reply to my last post here, don't worrry about it. I'll assume it made some sense.

I'm running behind now on your posts now - lol!!! I still have a few more hours of work to do now but will try and reply to some of your stuff a little later.

Thanks ,
PP

• • SVA Brewer With Over 100 Brews From Australia
  • Quote
• • • 0
    • 0
    • 0
    • 0
    • 0

PP

I am not sure what question I was getting at regarding the mash volume but I think your suggestion to look up displacement helped

I understand (But I am sure I couldn't explain) the difference between water volume absorbed and water displaced (by the grains).

On our weekend brew I measured the mash after about 10 mins and a good stir, and I topped up the mash to ensure it was the level that was expected in section K, I assume this is good practice?

Ian

• • Quote
• • • 0
    • 0
    • 0
    • 0
    • 0

Ian, I know you have one other question here and I am trying to knock all questions off tonight so I'll just do my best here...

In your brew, I wouldn't have topped up the mash to match the BIABacus. Why?...

The estimates used in the BIABacus are the best we have but they are very much averages (and I think there is actually one error on volumes I haven't had time to check in the last two months. This stuff is not as easy to check as you would imagine .)

I don't think any adjustments should ever be made pre-boil. You'll hear things like, "Just check your gravity pre-boil and make appropriate adjustments." That is not good advice but I have heard it in podcasts from even highly regarded brewers. It is simplistic, theoretical advice that totally ignores reality.

There are a hundred reasons why you should not make any corrections pre-boil. (Of course I am exaggerating but I want to counter impractical advice you can find anywhere else.) And one thing I am not exaggerating is that you should never make pre-boil corrections.

A single measurement on a single brew cannot be trusted. Other sites, podcasts, whatever, will make it sound like you can take a volume and gravity reading anywhere and it will be accurate. It won't be.

Then there is the issue of how much evaporation you will get during the boil. This can vary dramatically from brew to brew.

The idea of giving numbers (estimates) and taking measurements (actuals) is to keep you within some boundaries and to enable a fast identification of major procedural errors. As you become more experienced, if you saw a big discrepancy between estimated mash volume and actual mash volume, you would do the following...

1. You'd think...: That number is a bit odd (greater than 10% out). I might have buggered up my grain weight or water volume.

2. You'd take another few measurements at the end of the boil and if they conformed the above, then you would make adjustments.

Anyone who advises pre-boil adjustments (and this includes the most experienced brewer/podcaster/authors I have come across, I would question) should be asked why they are making this recommendation.

Running way out of time (and brain power) now Ian but I'll see if I can get to your next question.


PP

• • SVA Brewer With Over 100 Brews From Australia
  • Quote
• • • 0
    • 0
    • 0
    • 0
    • 0