Author Topic: Wrong volumes when adding sugar or extract  (Read 1974 times)

Offline Zelig

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Wrong volumes when adding sugar or extract
« on: March 01, 2017, 03:11:44 AM »
Hi!
I'm an all grain BIAB brewer, working on a not-so-big pot on my kitchen stove, and sometimes, when I'm brewing an high OG beer, I use to add some malt extract or sugar to the wort, because there's no space for more grains...
I discovered that in this case, BeerSmith 2 makes a mistake when calculating volumes, because they doesn't change at all if I add DME, LME or sugar or nothing! I suppose that adding "something" to the wort, that will dissolve into it, will cause an increase in volume, right?
In fact I've found that in those cases I always end up with a higher batch volume and - of course - a lower OG than expected...
Am I doing something wrong or is it a bug?
Thanks
Corrado
« Last Edit: March 01, 2017, 03:13:20 AM by Zelig »

Online Oginme

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Re: Wrong volumes when adding sugar or extract
« Reply #1 on: March 01, 2017, 05:35:45 AM »
You are correct that the addition will cause some increase in volume and that BeerSmith does not calculate it into the volume equation.  Unless you are adding a large amount of LME, this change should not be too great and unless you are pre-diluting your DME or LME, this change in volume will not result in a low gravity reading.  You are adding either a high sugar content solid (in the case of DME)or a very sugar dense liquid (in the case of LME) to a solution with a much lower concentration of sugar.  This will always result in an increase in gravity.

Since you have been getting low gravity readings, I would suggest looking at your efficiency from your BIAB mash.  I find it not unusual to have much lower mash/lauter efficiency when making higher gravity recipes, as the water which remains with the grain also contains a higher amount of sugars.  My typical mash efficiency runs around 86% for most normal gravity recipes, but will drop down as the gravity increases to around 78% for very high gravity recipes (above 1.090).
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Offline Zelig

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Re: Wrong volumes when adding sugar or extract
« Reply #2 on: March 01, 2017, 06:29:20 AM »
Thanks Oginme,
you're right about efficiency, my last batch was expected 1.100 OG considering 5% less efficency than usual. Probably I had to consider 10% less... :-)
BUT, considering the 0,8 liters more volume I had at the end of boil (on a 15 liters batch), the OG error would be much lower! Since usually my evaporation rate is calculated perfectly by BS, I suppose that that should be the volume of the DME (1kg) and sugar (0,3 kg) I've added. I've found a chemical formula that gives me exactly that value if it was all sugar!
I really think that the software should consider that into calculations...
« Last Edit: March 01, 2017, 06:36:07 AM by Zelig »

Offline BeerSmith

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Re: Wrong volumes when adding sugar or extract
« Reply #3 on: March 02, 2017, 10:53:02 AM »
The next version of BeerSmith will show LME and DME volumes (actually volumes for all fermentables) and should handle this better.

Brad
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Offline Zelig

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Re: Wrong volumes when adding sugar or extract
« Reply #4 on: March 02, 2017, 02:18:42 PM »
Thank you very much, Brad. That's good news!

Offline Zelig

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Re: Wrong volumes when adding sugar or extract
« Reply #5 on: September 10, 2018, 02:17:35 PM »
Ok, so I have upgraded to BeerSmith 3 and... the bug is still there.  :(

Offline GigaFemto

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Re: Wrong volumes when adding sugar or extract
« Reply #6 on: September 10, 2018, 05:14:22 PM »
Yes, this is a big disappointment. The Design tab lists the volume of extract, but the volume calculations don't use it! If the volume is relatively small it isn't a big deal, and if the volume is large enough to matter you can compensate manually by adding less water. There is another bug lurking in here that I hoped would be fixed in version 3 but isn't. If you have an All-Grain recipe with non-zero trub loss, the contribution from extract (LME, DME or sugar) will be over-estimated. The extract is considered to be transferred from kettle to fermenter with 100% efficiency, while the sugars from the grains will be transferred with a lower efficiency due to the trub loss: transfer efficiency = batch size/(batch size + trub loss).

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