Do non-fermentable spices increase the final gravity of a brew?

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DRoyLenz

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I have brewed two beers that are heavily spiced. One of which was VERY heavily spiced with cloves, ginger, cinnamon and molasses (Holiday Spiced Ale) that latest batch was pretty heavily spiced with coriander, grains of paradise, and star anise (Belgian Wit). Both of these brews proved to not ferment out as much as I would've hoped. The holiday ale fermented from 1.090 to 1.027ish (I can't remember and don't have my notes with me) and the Belgian Wit went from 1.046 to 1.018 (expected 1.010 - 1.014).

There are two possible explanations. The most likely explanation is that I am doing something incorrectly with making my yeast starters. These are the only two batches I've created with yeast starters.

There is one more explanation that I'm considering, and that is that the additional dissolved spices are increasing the density of the water, giving an artificially high SG reading.

Does anybody know anything about this and can shed some light on it for me?
 
I dont think the spices add to your gravity and if they do it would be very minimal. I did a pumpkin ale that went from 1.054 to 1.012 (actually lower than i want)

Im not surprised a holiday ale stopped a bit high, with a beer that big, sometimes the yeast just poops out. As for the Wit, i dont know.

Are you brewing extract, AG, PM?
 
The way to experimentally prove this one way or the other would be to make a spice tea and measure the gravity vs. a control sample of water. For what it's worth, even if they do affect the gravity (I don't think they would, at least not nearly to the amount you have seen) the amount of spices even in heavily spiced beers is nearly infinitesimal compared to the amount of malt and other sugars you put in.

So, I think there's some other reason for the results you're seeing.
 
I would be more concerned the heavily spiced recipe would slow down fermentation as many of the spices you listed do have some anti-microbial properties.

I am not sure what effect that would have on the yeast health and fermentation ability. Just another theory on why your ales stopped higher than you expected.

What would help is posting the recipes. If your recipes had higher amounts of dark or crystal malt then you should expect a higher FG because of unfermentables, especially depending on the yeast you used.

Since you have the equipment, test your theory. Scale down your spice contribution to say a quart of water. Measure the SG of the water (presumably 0), then steep the spices in the water at say 150*F. Cool the "tea" then measure your SG. This will tell you the contribution of the spices.
 
The Holiday Spiced Ale was an extract batch. The Belgian Wit was my first AG. I'm hoping I'm not this stupid, but I'm thinking it might be possible that I accidentally took the FG reading of the Belgian Wit AFTER adding my priming sugar. Considering the amount of sugar I used, it would account for the increase of .004 in my gravity reading.

Can you take a gravity reading of a beer AFTER it's carbed? Or does the dissolved CO2 drastically change the reading? Maybe I could let the carbonation come out of solution before testing FG out of the bottle.
 
Can you take a gravity reading of a beer AFTER it's carbed? Or does the dissolved CO2 drastically change the reading? Maybe I could let the carbonation come out of solution before testing FG out of the bottle.

You could take enough beer for a hydro reading and set it in a warm spot out until it goes flat, or shake it up to cause the CO2 to come out. Never tried it, but I would think the reading should be the same as the FG.
 
The Holiday Spiced Ale was an extract batch. The Belgian Wit was my first AG. I'm hoping I'm not this stupid, but I'm thinking it might be possible that I accidentally took the FG reading of the Belgian Wit AFTER adding my priming sugar. Considering the amount of sugar I used, it would account for the increase of .004 in my gravity reading.

Can you take a gravity reading of a beer AFTER it's carbed? Or does the dissolved CO2 drastically change the reading? Maybe I could let the carbonation come out of solution before testing FG out of the bottle.

What was your mash temp for the Wit?
 
My mash temp was 155F, and dropped as low as 150F a couple times before I added a little bit of hot water to raise it back up.
 
155°F is a *little* high. I mash at 148-150°F if I'm going for a dry beer, and no higher than 154°F in general.

I'd be interested in hearing about an experiment in regards to spice gravity, however. My buddy made a coffee porter and it really seemed like the coffee contributed to the gravity.
 
155°F is a *little* high. I mash at 148-150°F if I'm going for a dry beer, and no higher than 154°F in general.

I'd be interested in hearing about an experiment in regards to spice gravity, however. My buddy made a coffee porter and it really seemed like the coffee contributed to the gravity.

I think I'm going to do a little experiment with this. I'm making up another yeast starter for my next brew on Friday, and that would be an optimum chance to try this out. Just have to make another trip up to the Spice House.

If I was trying to do this as scientifically as possible, how would you recommend I do the spices. Maybe try a constant amount of various spices and see how each contributes to the gravity, if at all? Which spices would you recommend I try?

If you guys have any brew days coming up with recipes that include a large spice profile, let me know what spices you're using, and I'll see if I can run an experiment on those for you.
 
I think I'm going to do a little experiment with this. I'm making up another yeast starter for my next brew on Friday, and that would be an optimum chance to try this out. Just have to make another trip up to the Spice House.

If I was trying to do this as scientifically as possible, how would you recommend I do the spices. Maybe try a constant amount of various spices and see how each contributes to the gravity, if at all? Which spices would you recommend I try?

If you guys have any brew days coming up with recipes that include a large spice profile, let me know what spices you're using, and I'll see if I can run an experiment on those for you.

Weigh out a set amount of each spice, such as 1gram. Steep individually in a set amount of water, such as 10grams. Just pick enough water for your hydrometer to work. Then test each spice individually for any SG change.

IF there is a change, you will need to do multiple weights of each spice to determine a contribution chart. Example: 0, 1, 2, 5, 10grams of each spice in the set amount of water. This should give you specific curves for each spice.

The complication comes when you mix spices, because the contribution of one will limit the contribution of another. So, I would combine them all at equal amounts (grams), then do the same levels as you did for each spice(0-10grams) This will give you a curve for total spice contribution.

There are other ways of doing this, such as a Factorial design. Just more complicated.

Sounds like a fun experiment. I could try this with a refractometer that I have access to, but I would imagine the color of the spice would contribute to error.

I may try this with some loose tea here in my desk. I will get back to you soon with the details.
 
Weigh out a set amount of each spice, such as 1gram. Steep individually in a set amount of water, such as 10grams. Just pick enough water for your hydrometer to work. Then test each spice individually for any SG change.

IF there is a change, you will need to do multiple weights of each spice to determine a contribution chart. Example: 0, 1, 2, 5, 10grams of each spice in the set amount of water. This should give you specific curves for each spice.

The complication comes when you mix spices, because the contribution of one will limit the contribution of another. So, I would combine them all at equal amounts (grams), then do the same levels as you did for each spice(0-10grams) This will give you a curve for total spice contribution.

There are other ways of doing this, such as a Factorial design. Just more complicated.

Sounds like a fun experiment. I could try this with a refractometer that I have access to, but I would imagine the color of the spice would contribute to error.

I may try this with some loose tea here in my desk. I will get back to you soon with the details.

Everything you said makes perfect sense. However, I don't see the need to try any mixed teas, I should be able to extrapolate how the combined contributions will affect the gravity when mixed, assuming I know how they will contribute individually.

If I find that any two spices DO contribute to gravity, I will mix them and see if you can just combine them linearly, and if not, how they will be related.
 
correct me if i'm wrong, but your final gravity is based on the attenuation percentage of the yeast, not a set number like 1.015-1.018.

1.090 with a 75% attenuable yeast will bring you to 1.0225 apparent attenuation. which is close to what you hit. so, success?
 
Teabrix.png


OK. Here is what a single bag of white tea steeped gives when I diluted it.

Setup:
1 tea bag
100ml distilled water
Steep Temp: 65*C(150*F)
Steep Time: 3mins
Dilutions:0%, 30%, 50%, 70%, 90%, 95%
Digital refractometer accurate to 0.01*Brix

Dilution Setup:

Total volume: 10mL
Added 9mL of tea with 1mL of water.
Continued through dilution.

Interestingly, the tea did alter the Brix reading of my refractometer. I can not determine if the contribution is a form of sugar from the tea OR optical properties of the tea.

It is a linear trend up to the highest point, but I suspect there will be a non-linear curve that will appear when the concentration becomes higher. This is typically found in nature. A famous form is the Michaelis-Menton equation. Link to Wiki Which is why I would suggested the combined spice tea. IF one of the spices contributes much more than another, then it will inhibit the lower contributing spice and throw off any thought the spices are altering the SG equally.

Obviously, there would be more work to be done by increasing the amount of tea that I add, but for now this gives me an idea of how much non-malted products can contribute to the SG of a wort.


I so enjoy working in a lab:ban:
 
I so enjoy working in a lab:ban:

I am seriously very jealous of you right now. I did engineering in college, but now am in the business world. If there is one thing I miss about engineering it is lab space/time. I would love to be able to run experiments as easily as I did back at school.

Good work! I think this lends a bit of credence to the theory. I'm excited to see how my results come out.
 
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