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Biabacus and ambient temperature?

Post #1 made 11 years ago
by milligan
I was wondering where Biabacus takes ambient temperature from? I tried changing "If grain is..." in s. E. but that makes no difference to the values I am interested in TWN and SWN in s. K

What I am looking for is how much I need to correct TWN as I use my hot tap water as I have solar hot water. This gets 50-55c so I don't have to take it much further to mash temperatures. In the example I am looking at TWN = 15.07 and SWN = 15.36. Biabacus is telling me to 70.4c. So I know that I need somewhere between 15.36 litres at ambient and 15.36 litres at 70.4c. I am trying to work out how much water is needed at 50-55c???
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Post #2 made 11 years ago
by PistolPatch
Hi there milligan,

What we've done in the BIABcus is made three temperature sets...

1. Ambient = about 15C and suits both lager and ale fermentation temp volumes. (In fact, theret is hardly any difference in volume between 5C and 30C).
2. Mash Temp = about 65C but the volumes work well for temps between 50 and 80C. (inother words, the volume difference is minute/negligible.
3. Boiling = 100C

Water/wort swells by about 2% from ambient to mash temp and then another 2% from mash to boiling.

In a pure, full-volume BIAB which you are doing, SWN is the TWN swollen by that approx 2%. In other words, if you are using solar hot water, just fill it to the SWN level - 15.36 L.

The small difference between water at 55C and 65C is not even really measurable for most batch sizes. For example, 100 litres at 50C is 100.76 litres at 65C. The tiny difference that cooler grain would make over warmer grain would add up to basically nothing as this only changes the strike temperature required by a few degrees.

So, go the 15.36 L of solar hot water.

:peace:
PP

P.S. There is a formula to work on exact temps but there was a reason we simplified to the above. Can't remember why though now :scratch:. I'll have another look at it but it really doesn't make a difference in practice.
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