On your next brew, if you are a pure BIAB'er and do a "mash-out", I'm wondering if you could take two gravity readings and record them here for us.

What is a Pure BIAB?

A pure BIAB is when all the water required in a brew is added to the mash. In other words, there is no active sparging involved.

What is A "Mash-Out"?

When BIAB'ing, you can either pull the bag at the end of the mash and then bring this 'sweet liquor' to the boil or you can allow the bag to remain in the sweet liquor and raise it's temperature to about 76 C - 78 C before removing the bag and then proceeding to the boil.

If you have a pulley set-up, doing a mash-out is easy. You can simply raise the bag so it is not touching the bottom of the kettle and apply heat with an occasional stir. Without a pulley, you will have to stir the whole time to prevent your bag being burned.

What Gravities Do We Need?

Could you please take two gravity readings for us...

1. Take one at the end of the normal mash.
2. Take one after you reach the mash-out temp.

Please post in this thread as follows...

Here are two examples for you...

EG 1. 60 minute mash followed by a mash-out.

Gravity at Mash End (60 minutes): 1.050
Gravity at Mash-Out (75 minutes): 1.055

EG 2. 90 minute mash followed by a mash-out.

Gravity at Mash End (90 minutes): 1.051
Gravity at Mash-Out (100 minutes): 1.053

(The above figures are fictitious so do not expect them.)

Be Careful when Taking Readings

1. Let your samples cool to 15 - 20 C. Hydrometer temperature corrections are not accurate.
2. Collect the sample in a coffee mug and cover it with plastic or foil whilst it cools. Use the fridge or freezer to speed up the cooling process.
3. Use a wide hydrometer jar. Most jars provided with commercially sold hydrometers are too narrow for accurate readings. Spin the hydrometer and take a few readings before making your final recording.
4. Post your figures even if they make no sense to you. Odd readings can occur for many reasons.

Why We Need Your Numbers.

The BIABacus has many formulas hidden within it to automatically estimate outcomes. Whilst all these estimates can be over-ridden, it is our aim is to get as many of these as accurate as possible. Good estimates help new brewers as well as saving experienced brewers doing unnecessary over-rides.

In this experiment, we expect an increase in gravity between the two readings for two reasons. Firstly, the grain has more contact time with the liquor. Secondly, the viscosity of the liquor increases at mash-out. We suspect that the former will be the major cause so please feel free to add in any other gravity measurements you can during the mash. For example, if doing a 90 minute mash, if you can record a gravity at 60 minutes, this would be very helpful.

Many thanks,
BB

[All posts above are excellent as they are. Please keep them coming. If you have time, please read the below as there may be even more that you can contribute.]

Thanks to all of you.

2trout's post is very timely. (More re your questions below trout.)

Thanks so much to you all for taking the time and trouble to contribute your numbers here. This is an extremely important thread and to see it being regularly bumped by you with no feedback or encouragement makes a massive difference.

We envision quite a few more of these style threads in the future. The aim of such threads is to improve or create new default information given on the site either in official threads or in the BIABcus. A lot of the research thinking we are doing or intend to do here has never been done before. The results will definitely end up being copied onto other sites and into other software, hopefully with acknowledgement or permission, so, what you are doing here will make a big difference.

It's a very important thread.

In this thread, we are exploring the most basic of mash parameters. Does time make a difference? Already we can see that an increase in mash time indicates a difference. We need a lot more numbers to obtain a good average default, however, thanks to your input, we can already say that there is almost definitely a difference and probably a high one. This is extremely important. Why?...

No existing software recognises that time affects efficiency. Nor does any software recognise that gravity affects efficiency. And, we haven't even looked at the mash-out effect.

In other words, all existing software, except some spreadsheets you might find buried here, expect you to brew exactly the same gravity brew for any mash time and get the same result. Or, if you have a ridiculous amount of savvy, ask you to set up a different equipment profile for every gravity brew and mash method you use.

To an experienced brew mathematician, the above is a serious flaw. All the hard calculations have been ignored to date and, they have to be because the most basic data has never been gathered. That is what we are doing here.

What more data do we need in this thread?

This thread is a general thread. It's main aim is to test a general point of view we had and then work out what questions to ask next. 2trout's post above is excellent. It's not critical now but wherever you can, please write as much detail on your mashing methods as possible. Doing this will help us formulate the next questions we need to explore.

Basically, the more you write, the faster we can learn. BUT, we also know that taking measurements is annoying, hard and difficult. Just post what you can do easilly for now.

What you are actually doing here.

Behind the scenes on this site we have been working extremely hard to create a whole new model of brewing education, terminology and software. Very few brewers even realise there is a problem. If you are contributing here, you are making a difference in a bigger way than you are probably currently aware of. Your input here, and our work, will enable as many brewers as possible, of different levels of experience and equipment, to seamlessly come together. (And yes, that even means that a three-vessel, experienced, traditional brewer should love the BIABacus, simple spreadsheet that it is, and the terminology.)

Doing all this has been, and still is, very tricky and time-consuming but we are getting there.

Thanks again for those of you who have jumped in already on this thread with your figures. Hopefully we'll have enough posts here soon to add a time dimension into the BIABacus default auto-efficiency feature.

Cheers,
BB