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VIF much higher than expected- please help?

Post #1 made 10 years ago
by Inconceivable
Hello

today I did my first ever BiaB a mini stout. I screwed up the grain bill and left 9% of the grains out which probably accounts for 13 x missing points of OG

What really troubled me though is I ended up with 1.8L of VIF more than my Biabacus called for. Per attached I started my mash with 11.74L (SWN). Didn't note VAW along the way but after chilling my ruler showed just under 8L and that's what ended up in fermeneter despite me configuring Biabacus to give me 6L

I'm reconciled to the fact the brew is partially stuffed due to me mixing up the grain bill but I'd love to get to the bottom of the volume problems before my next brew if anyone could please help? Do I need to change kettle efficiency somewhere?

ta
Nick
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    • SVA Brewer With Over 20 Brews From Australia

Post #2 made 10 years ago
by joshua
IC, you may have not had enough Heat to boil off the wort to 6L, Most of have done that(A Lot).

I use the The ruler during the Boil to check when I Get to VFO. I do not time the Boil, but, record how long it takes and change the times to add hops.

Stove top brewing is great to do, but, most Knobs do not have enough heat be do what we need.

So, you got 8L instead of 6L, so the Volume was 8L/6L or 1.33 over volume. You were hoping for a gravity of 1.052 or 52 Gravity Points.

52 gravity points/1.3333 is 39 gravity point which is 52-39=13 Less, which is about the Difference you received.

If you can Measure the Volume in the Kettle as it boils, you will hit your VFO, and your VAW when it Cools;

If you have a Stainless Steel Bowl that will float in your Kettle, try floating it next time you brew.

It will really help the boil due to the lower Area the Wort has to bowl off.

Good Luck!
Honest Officer, I swear to Drunk, I am Not God.
    • SVA Brewer With Over 100 Brews From United States of America

Post #3 made 10 years ago
by Inconceivable
Hi Joshua
thanks for the reply. your idea to boil down to VFO has some merit I think; I was thinking the only option I had was to reduce my SWN

Thinking on it I think I should do both; since my electric stove top struggles to give me a good boil and I do have a stainless ruler marked up that will let me gauge the volume in the kettle. Only problem with boiling down to VFO; as you said is screwing up the hop addition timings; I seem to recall I wouldn't want my bittering hops to be in for more than 90 mins so you've got to have a cut off point.
Anyway I'll keep tinkering to try to get a good realistic SWN for my kettle then can presumably punch this data back into the Biabacus so it'll do it right for me

cheers
    • SVA Brewer With Over 20 Brews From Australia

Post #4 made 10 years ago
by joshua
Nick, It you have time,

You can try Boiling off (10.94-7.28 = )3.66/3.75L from 11L, and steam up your area, and measure "How long" it takes to Boil off.

That will give you an Idea on delaying the Hop addition, or How much SWN you need to Cut back.
Honest Officer, I swear to Drunk, I am Not God.
    • SVA Brewer With Over 100 Brews From United States of America

Post #5 made 10 years ago
by Inconceivable
Update for the record. My second BiaB of the day I reduced the SWN with some back of the envelope voodoo maths and then was sweating on the VFO target and nursing along a more vigorous boil to hit it. I ended up coming in a whisker under the VFO target (hooray).
Then hilariously I didn't realise the tap on my new fermenter was open and lost 200ml+ of my 4L batch whilst aerating by pouring between kettle and fermenter after the chill (whoops).

So by the numbers and with more detail: today my first BiaB batch had SWN 11.74L and my VIF was 7.8L (66% of SWN) - target was 6L VIF.
My second Biabacus called for SWN 9.06L and target VIF 4L; I didn't feel at all confident of hitting the target VIF based on the first batch so I monkeyed with the numbers and decided to cut my SWN by 17%, down to 7.56L. I then proceeded and with the reduced SWN and me nursing along a more vigorous boil from my crappy electric stove top I nailed the 4L target VIF with 150ML+/-

My conclusions on hitting the VIF you want would be to follow Joshua's advice and keep a ruler handy to ensure your boil is going to put you within the ballpark of your target VIF. Personally I'll also be meddling with my Biabacus SWN as I get used to BiaB to tune it for my kettle.

Nb: Since my electric stove top struggles to bring and maintain a boil I need to leave the kettle lid mostly on at all times but a few millimetres more or less covering of the boiling wort will be the difference between a surging, overflowing boil, and a sub-par simmer that's not up to scratch. In other words a high maintance pain in the backside.
    • SVA Brewer With Over 20 Brews From Australia
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