Ques.: why are steeped grains affecting OG?

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Re: Other related problems

Postby just-cj » Fri Dec 15, 2006 8:14 pm

jeff wrote:I would guess that even a cup of coffee might have an S.G. greater than 1.000 even though, to my knowledge, coffee doesn't have much by way of dissolved sugars. Am I way off?
I just measured my wife's black coffee with a digital hydrometer, and it came out 0.9 Brix -- approximately 1.004. So no, you're not way off! 8)
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But ... consider this ...

Postby billvelek » Sat Dec 16, 2006 5:15 am

slothrob wrote:
billvelek wrote:Actually, anything that remains in suspension will affect gravity. ... snip ...
Only substances in solution contribute to specific gravity as read by a hydrometer, not those in suspension. ... snip ...
Well, you're probably right, since I'm neither a chemist or physicist, and it's been better than 30 years since I've taken those courses in school. But to illustrate the point that I was trying to make, and which I think is valid, consider this example:

Take a container with a quantity of water, and pour a quantity of oil on top. Oil will never go into solution with water, but it will ... in a sense ... go into suspension if you shake the two of them up enough (think of a salad dressing that contains oil). Now if I added a pith ball that was just slightly heavier than the oil but lighter than water, it would rest at the level where the oil and the water stratify, or ever so slightly below that point. Now shake the dickens out of the container to the point that the oil, though not in SOLUTION, is commingled with the water for a brief period of time ... in suspension ... until they separate. Where would the pith ball be during that time? There would be no clear line of stratification yet, but it would tend to float if there is more water than oil, and it would tend to sink if there is more oil than water. Anyway, that has nothing to do with beer or BTP, so let me ask that we get back to the subject of why BTP attributes increased gravity to specialty grains which have not ... and can not, under the circumstances ... convert? Even if it were valid to attribute some gravity to a specialty grain that has been steeped, it certainly isn't valid to attribute the same relative gravity reading as when the specialty grains are mashed and thereby converted by the diastatic power of other malts.

Anyway, I could be wrong; it has happened a couple of times in my life. :lol:

Cheers.

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Postby just-cj » Sat Dec 16, 2006 5:54 am

It really depends on what specialty grains you're talking about. As someone mentioned above, crystal malts are already converted, so when you steep them, you're essentially just liquefying the sugars and getting them into solution. No conversion is necessary at all. Other malts do some diastic power, so even steeping them will result in some conversion even though to get full conversion they need to be mashed. Still others need to be mashed, but when steeped will contribute to a gravity reading because of the starches that are liquefied and get into solution.

I have a small experiment that I'll hopefully do tomorrow to test a couple of grains I have extra of. I won't do a pound in a gallon, but I will do a controlled steeping experiment to see what measurements I come up with on my digital refractometer. Hopefully I'll be able to post some results in 12 hours or so. 8)

Edit: As for being wrong, I'm always ready to be proven wrong. :mrgreen:
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Postby slothrob » Sat Dec 16, 2006 5:09 pm

Cool experiment, thanks. I thought I remember seeing a table somewhere that showed the contribution to gravity of steeped and mashed grains, but I can't find it, now.

Oil and water have a spacial relationship because they can form something called an emulsion, that acts a lot like a solution, but isn't quite. It can be considered a third state that acts differently than sand or sugar, but to a hydrometer, might look more like sugar does, but a hydrometer can't really see that there's sand present. Generally, non-dissolved matter doesn't affect the density of the water, except, perhaps, very locally around the particles themselves, but we're talking about the molecular scale at that point. It's been something like 16 years since I took physical chemistry, but I'm pretty sure that's right.
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Postby just-cj » Sat Dec 16, 2006 11:58 pm

Well, I did two steeps today -- flaked barley and chocolate wheat. I added 120 grams of grain to 1 liter (equivalent of one pound in one gallon) of hot tap water (~140F) and steeped for around 45 min. I weighed both the grains and the water (1000 grams = 1 liter) to make sure that I was consistent -- I crushed the chocolate wheat but not the flaked barley. Throughout the steep, I swirled several times to make sure that the goodies were getting into the water and to ensure that the grain was hydrated well. Here's what I got:

flaked barley = 0.1 Brix
chocolate wheat = 7.4 Brix (1.029)

Both of these have zero diastic power, so there was no conversion going on there. The number for chocolate wheat doesn't surprise me, but I expected flaked barley to contribute more than it did.

If I get some more time later today or at the beginning of next week, I'll try some other grains, like oatmeal (another flaked grain), aromatic, caramunich, or biscuit. I also want to try just some wheat or 2-row -- grains that need mashing -- to see how they react.

Edit: Okay, I just tried oatmeal -- same procedure.

oatmeal = 0.3 Brix

Now, I did think of something. I should have done a hydrometer reading as well -- the digital hydrometer might be reading something different from what a hydrometer does (although it shouldn't). If/When I do some more steeps, I'll measure both ways.
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Brix Refractometer

Postby jeff » Sun Dec 17, 2006 11:18 am

just-cj wrote:Now, I did think of something. I should have done a hydrometer reading as well -- the digital hydrometer might be reading something different from what a hydrometer does (although it shouldn't). If/When I do some more steeps, I'll measure both ways.


A brix refractometer measures sugar in solution. This will explain why the starchy tests yielded such low values. Thanks for all the investigation into this!
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Postby just-cj » Sun Dec 17, 2006 1:12 pm

Well, all I can say is CRAP! :cry: I had enough liquid to do a hydrometer test as well, but spaced it out until I was all done and typing up the additional info about oatmeal. Well, I have lots of oatmeal here, so I'll do another one of those and fart around with a couple other grains later on. I'll post more in a day or so.
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Thanks, just-cj ... and one final comment about bouyancy

Postby billvelek » Sun Dec 17, 2006 1:43 pm

Thanks for taking the time for these experiements, 'cj'. Hopefully this will shed sufficient light on the matter to ensure that BTP is correct and accurate. I can also understand Jeff's statement that a refractometer measures just sugar, but I must question slothrob's comment that only solubles will affect gravity ... and so perhaps BTP is entirely correct in the OG that it predicts for specialty grains because of the starch. But obviously it can't be correct in predicting FG if it does indeed include the starches in the OG.

Anyway, slothrob's last comment sounds like he is a lot more scientiically educated, or at least has done some research on the subject; I, on the other hand, am just applying some logic to what I am absolutely confident I can remember correctly from high school about bouyancy, which is exactly what the hydrometer is measuring -- how much matter it is displacing based on the weight of the liquid. Now, I want to give one final and probably better example of why I believe that matter in suspension -- even though completely insoluble -- will still affect gravity. Sand was not a good example because it doesn't remain in suspension long enough -- but muddy water is perfect. If you take water with a layer of undisturbed silt on the bottom and then float something in it (e.g., a hydrometer), it will displace its weight in water. If you then stir the silt up and make the water muddy, it will then displace its weight in muddy water, including the silt which is insoluble. I can't logically get around that, but maybe I'm just being dense.

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Postby just-cj » Sun Dec 17, 2006 3:03 pm

Okay, I repeated the oatmeal steep, and here's what I got:

Refractometer = 0.3 Brix (~1.001)
Hydrometer (narrow range, 1.000 - 1.032) = 1.011

So, it looks like the hydrometer is picking up more "stuff" in solution. I'll do a couple more grains when I get a chance, hopefully later on today.

Edit: I was sleeping this morning and totally mistyped/spaced out the hydrometer reading. (I had reported 1.003, but it was actually 1.011.) Sorry for the screw up.
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Re: Thanks, just-cj ... and one final comment about bouyancy

Postby just-cj » Sun Dec 17, 2006 4:31 pm

billvelek wrote:Thanks for taking the time for these experiements, 'cj'. Hopefully this will shed sufficient light on the matter to ensure that BTP is correct and accurate. I can also understand Jeff's statement that a refractometer measures just sugar, but I must question slothrob's comment that only solubles will affect gravity ... and so perhaps BTP is entirely correct in the OG that it predicts for specialty grains because of the starch. But obviously it can't be correct in predicting FG if it does indeed include the starches in the OG.
But FG predictions are really just rough estimates, based on the yeast's reported attenuation (which can be adjusted by the BTP user), but so many things affect FG besides the yeast -- grain bill (lots of crystal malts will leave a much higher FG), high mashing temperatures (not applicable for extract brewers, of course) or less fermentable extract (Laaglander is notorious for not fermenting out), fermentation temperatures, yeast health, oxygenation, etc. If BTP ignored the sugar contribution of all steeping grains, it wouldn't be accurate.

A very important point about starches needs to be made though (I don't remember reading it in this thread yet) -- extract brewers who steep grains should avoid steeping grains that contribute starch to their wort! Yes, that limits them to crystal malts and roasted malts for the most part, but that's one of the inherent limitations of extract brewing. I really hate seeing shops selling extract kits with Munich malt, aromatic malt, biscuit malt, and even good old Briess Carapils as steeping grains. All of them need to be mashed or they'll contribute mostly starches and a little flavor and color. Starch in beer is bad -- bad bad bad! Sorry for the rant -- nothing to do with BTP. :oops:
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You're not ranting

Postby billvelek » Sun Dec 17, 2006 9:45 pm

I agree with you that BTP should consider the sugar contributions of all grains; I don't think I ever said anything different, or at least I never intended to. What I meant is that when specialty grains that have no diastatic power are steeped, and obviously I mean outside the presence of malt that can contribute diastatic power to convert their starches too, then ... with the exception of those grains that already contain sugar (but I think most do not) ... BTP should be programmed to differentiate between whether those grains are merely steeped or are mashed. It doesn't appear to be able to do that, so I merely suggested that BTP could be improved in that area. And I understand and agree that starch is not desirable in beer, although I have never really experienced any starch problems, so I'm not sure I can really appreciate the consequences. IIRC, starch causes haze, gives any bacteria something to chomp on ... increasing the risk of spoiling, and would contribute unnecessary carbs/calories to beer. I don't know if it does anything else to head retention, flavor, color, mouthfeel, aroma, etc., but in any event it is something that we definitely don't want in our beer. I guess if you find that you have starch after mash-out, the only recourse is to add amylase to the fermenter, but then you would probably produce an extremely dry beer. Can you suggest any other consequences or solutions?

As for the variables that keep BTP from making an accurate prediction of FG, that's sort of a dichotomy. On the one hand, we are asking/expecting BTP to tell us when our 'recipe' fits a particular beer style, which includes considerations of OG, FG, and alcohol content. On the other hand, we have to make our own prediction of attenuation to get an accurate prediction from BTP. Of course, I realize that there are many factors that BTP can not consider without information from the user, but I had actually thought that if I provided a detailed recipe right down to the brand of malt, and a detailed mash-schedule right down to the thermal mass and heat transfer rate of my tun, and listed the specific yeast I use and the fermentation temp, that BTP would give me a rough idea of the attenuation I could expect. Instead, I have to set it myself, and while I might be able to do this from experience with the same or similar recipes using the same yeast over and over, most yeasts I have never tried before and when doing so it would be nice if BTP would at least give me a ballpark estimate of what I could expect with that particular yeast under those circumstances (ingredients, mash schedule, pitching rate and temp, etc.). I guess I was just expecting more from the databases, and perhaps I had unreasonable expectations. But what is the purpose for so much detailed info re the mash schedule other than for the determination of how much water and at what temp to make the next infusion? ... which, by the way, is probably worth the price of the software anyway. And by the way, I love this program and don't regret for an instant getting it. It would just be nice to at least have some sort of recommendations from BTP -- that for a particular style of beer, it is traditionally mashed at such and such a temperature, etc. I just can't see where BTP is even providing a "rough estimate".

And you are not ranting. We are engaged in a very civil discussion from which I am also learning a bit. Thanks.

Cheers.

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