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yet more questions

Post #1 made 11 years ago
by BDP
Hi,

Second batch in the bag, excuse the pun: a slightly modified version of BCS "Hoppiness is an IPA".

After getting a low evaporation on my first brew, I modifed the evaporation rate in section X to 5L/hr, and ended up a lot closer to the estimated volumes. I used PistolPatch's suggestion of floating a stainless steel bowl, and the boil was indeed a lot more vigorous, but the evaporation rate was the same as before. Why exactly is it better to have a vigorous boil in this case?

My efficiency measurements were between 70% and 72%, which seems to me to be on the low side. I did around 3 temp checks/mash agitations, and a final mash out. Expected GAW was 1.065, and actual GAW was 1.058. Should I be stirring the mash more frequently?

What is the 'Actual OG' in section O used for? I assume that 'At Pitching' means after the yeast has been pitched to the wort in the fermenter?

Also got to wondering about section Y of the BIABacus, and when it would be appropriate to use these adjustments. I assume if one follows a high integrity recipe, as I did, there is no need for adjusting grain extract potential. What about when designing a new recipe that uses grains with lower than normal extract potential, where a specific OG is desired?

In closing, I'll say again that this forum and the BIABacus add to the pleasure of homebrewing :salute:

Cheers everyone.
BDP

Post #2 made 11 years ago
by Rick
Here is a good read about boiling.

Regarding low kettle efficiency, here are some points to look at.

As for stirring the mash, I'm pretty OCD about stirring. I like to distribute the heat as much as possible, so I'll stir every 10-15 minutes. Here is a recent discussion on the matter.

Actual OG is another opportunity to take measurement, as a single measurement is not to be trusted. In theory, you should get the same reading. I only measure twice if my first measurement is off. Ignorance is bliss if the first one checks out. :D

Section Y. is needed if there is a great amount of sugars/adjuncts/extracts in your brew. Default PPG is 35.49, which is good for most malts, and even small amounts of sugars.

Dextrose would be more like 46ppg. In small amounts, there would be little difference, but if you used a lot of it ... you would need to account for the 100% fermentability. I suppose you might be correct about following a high integrity recipe, but you also need to enter it into the BIABacus properly so the right hand side of section C is calculated properly.

That's all I got.
Last edited by Rick on 02 Jul 2014, 22:40, edited 1 time in total.
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Post #4 made 11 years ago
by BDP
Hi,

Rick, thanks for the links - very interesting indeed! M_S, I've posted my file to the thread you referenced. Thanks in advance for taking a look.

When taking a gravity sample with a hydrometer, should one ensure that the wort sample is free from trub sediment? I only took the reading once the bubbles/foam had cleared, and by that stage there was about 2 to 3 cm of hop 'sludge' at the bottom of the flask in which the base of the hydrometer was resting. It did not appear to be offering any resistance or buoyancy, but I did wonder at the time if this could offset the reading. :think:

Cheers
BDP

Post #5 made 11 years ago
by Mad_Scientist
I had a look at your file. Good job filing it out.

Your volume actuals are good, but like you said the gravity readings didn't meet expectations.

I saw the brewing salts you added. Are you into water chemistry? Do you take pH readings of the mash? I blindly add brewing salts based on a very old water report. :argh: My efficiencies are very close to the estimated. :)

The low kettle efficiency could be any of those listed from the link Rick provided. Were both of your hydro readings taken as close to ambient temperature as possible? , as hot temps are not reliable with the conversion.

Maybe you can make this test with your hydro as PP mentioned it; http://www.biabrewer.info/viewtopic.php ... 300#p10648 If you get a 1.046 instead of a 1.050, you have part of your answer.
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Post #6 made 11 years ago
by BDP
Thanks Mad_Scientist. My water is very soft. I have an older municipal water report that I based my calculations on (using the Kaiser water calculator). I've been wanting to try the water adjustment for some time, and this is it :)

This time I was very careful to ensure that the temperature of the gravity samples was as close to the calibrated temp as possible (60F).

I never thought to check the hydrometer - what a great suggestion!

Post #7 made 10 years ago
by BDP
Hi Folks,

Brewed the Nutcastle Brown from BCS today. My efficiencies were slightly better than the previous brew:
EIB = 75.6%
EAW = 74.1%

Still about 10% under the estimated. I'm starting to suspect the crush that I get from my supplier, as I noticed a not insignificant number of un-crushed grains. My inexperience aside, I think this is definitely one contributing factor.

The gravity sample pre-pitching tasted lovely though :thumbs:

Cheers!

Post #8 made 10 years ago
by Mad_Scientist
Congrats on the brown!

Un-crushed grain could be why you are down 10%, good on you for noticing that.

Did you ever make that hydro test using simple sugar? Just curious...
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Post #9 made 10 years ago
by BDP
Hi Mad_Scientist,

No, but my brewing water read 1.000 (or as near as dammit). And then either I was lazy or ran out of sugar. More than likely the former :) I should really do that last measurement sometime ... Thanks for asking :salute:

The brown ale is tasting better than it did two weeks ago (so about a month after bottling now). Next time though, I'll go with a sweeter, maltier version of this style.

Cheers!
BDP
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