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
Mash Gravity Figures Needed for BIABacus.
Post #1 made 11 years ago
Last edited by BIABrewer on 30 Sep 2012, 21:00, edited 2 times in total.
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