Question about sweetness and gravity

I've been messing around with mash temps lately to change the final gravity on my beers, and thus the amount of unfermented sugars in the final product. The odd thing is, I've brewed several beers where the taste seems to contradict the hydrometer readings.

For instance, I just brewed a double IPA and it started at 1.070 and finished at 1.010. My target mash temp was 150, but I ended up hitting 151 which I held for 75 minutes. The gravity came out as expected, but the brew tastes decidedly sweet. I used Nottingham dry yeast, no starter, for this batch as well.

I've also had the opposite happen; I ended up with a 1.018 stout, but it actually tastes fairly dry. Not like a guiness or anything, but more along the lines of a blonde ale or Ed's Haus Pale. Any thoughts?

I've always assumed ending gravity to be a good indicator of the sweetness of the final product, but this has not held true for each beer. Anyone else notice this?

I have found that certain grains add a sweetness to the beer even though the final gravity tells me it is dry. Along with that, certain hops tend to taste sweeter than others, in particular the 'c' varieties. I made a IIPA recently also and it has in the range of 165 ibu's and finished at 1.012 and yet has a sweetness under the big hops bitterness and flavor. Just my experience.
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Come to think of it, I did use centennials on at least one of those brews and did a first wort hop. Might that be the key?

I would definately consider the Centenial hops as a possible source of the 'sweetness' you are experiencing. Did you use any caramel malts? They may also provide some suggestion of a sweet experience.
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mbird said:

I would definately consider the Centenial hops as a possible source of the 'sweetness' you are experiencing. Did you use any caramel malts? They may also provide some suggestion of a sweet experience.
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Yes, I use some crystal 60L in all of my brews. The only beer I really go over the top with it is in my brown ale...which last time turned out pretty dry. Aside from that, I stick with mostly 2-row and Pale Ale malt with a bit of specialty grains here and there.

Sometimes a flowery or fruity aroma can be interpreted by your nose as sweetness on your tongue. For example, a lot of wines come off as "sweet" when in fact there is no sugar left in them, it's just the aroma off of the nose that tricks the brain into thinking the liquid has sugar in it. One test: plug your nose and take a sip. Is your tongue telling you it's sweet, or is it your nose?

Is it possible you are producing alot of unfermentable sugars? I don't know the effect these have on hydrometer readings, but you can get a complete fermentation of the fermentables and still have unfermenatable sugars remaining thus giving you the residual sweetness.

MNBugeater said:

Is it possible you are producing alot of unfermentable sugars? I don't know the effect these have on hydrometer readings, but you can get a complete fermentation of the fermentables and still have unfermenatable sugars remaining thus giving you the residual sweetness.

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I was wondering about that. But I always assumed hydrometers measured sugars in general, and didn't differentiate between ferementable and non-fermentable. Anyone know?

TwoHeadsBrewing said:

I always assumed hydrometers measured sugars in general, and didn't differentiate between ferementable and non-fermentable.

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this is true. hydrometers basically measure the density of a liquid; anything dissolved in that liquid will increase its density (sugars of any kind, salts, etc)

And in addition to that...the fermentable sugars are decidedly sweeter tasting than the unfermentable ones.

Also, some dark grains like chocolate malt and roasted barley have their own bitterness which counters the sweetness.

*subscribes* Since I haven't started playing around with this yet.....cool topic!

SpanishCastleAle said:

And in addition to that...the fermentable sugars are decidedly sweeter tasting than the unfermentable ones.

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But aren't the fermentable sugars "gone" ie converted to alchohol?

Whether the fermentable sugars are sweeter than the unfermentable ones, isn't that a moot point in the end? All that's left to taste sweet would be the unfermentable ones.....

Right? I'm just trying to get my head around this...

I wonder what role alcohol plays in all of this...well besides the buzz. Our local brew club had a meeting at a micro-distiller once, and it was interesting to talk with the owner of the place. Very knowledgable, and he said an interesting thing, "Some people don't taste it, but alcohol actually has a sweet taste. If you taste very good liquor it tastes sweeter than the cheap stuff." So I wonder if maybe the low gravity is actually giving off more "alcohol" sweetness than a "normal" attenuated beer.

TwoHeadsBrewing said:

I wonder what role alcohol plays in all of this...well besides the buzz. Our local brew club had a meeting at a micro-distiller once, and it was interesting to talk with the owner of the place. Very knowledgable, and he said an interesting thing, "Some people don't taste it, but alcohol actually has a sweet taste. If you taste very good liquor it tastes sweeter than the cheap stuff." So I wonder if maybe the low gravity is actually giving off more "alcohol" sweetness than a "normal" attenuated beer.

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Maybe that's what Castle means as well...the fermented alcohol is "sweeter" than the unfermentables....

But aren't the fermentable sugars "gone" ie converted to alchohol?

Whether the fermentable sugars are sweeter than the unfermentable ones, isn't that a moot point in the end? All that's left to taste sweet would be the unfermentable ones.....

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What I was getting at is that there are two ways for a beer to have a high-ish FG...either it didn't fully ferment or it wasn't very fermentable to begin with. One should taste sweeter than the other with everything else equal (including FG). I was just pointing out another way for FG to not correlate exactly with perceived sweetness.

SpanishCastleAle said:

What I was getting at is that there are two ways for a beer to have a high-ish FG...either it didn't fully ferment or it wasn't very fermentable to begin with. One should taste sweeter than the other with everything else equal (including FG). I was just pointing out another way for FG to not correlate exactly with perceived sweetness.

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Ah, gotcha now!

Revvy said:

Whether the fermentable sugars are sweeter than the unfermentable ones, isn't that a moot point in the end? All that's left to taste sweet would be the unfermentable ones.....

Right? I'm just trying to get my head around this...

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This is where I was going with my unfermentable sugars commentary

Prosted this thread!!!!

It's so nice to have a topic/discussion where I get to actually be the one to learn stuff...instead of telling someone their beer is fine.



Carry on....Pleeze.

Hey All!

I think there is one more big issue on this that no one seems to have brought up. That is the fact that the specific gravity of alcohol is lower than water (which is why those of us who also brew mead & cider that we often have a final gravity of 0.994). This means that if you have a high gravity brew (the 1.070 one in the OP's case) versus a session beer gravity (say 1.045), if both fermented completely out, the high gravity brew would have a lower FG than the session beer (FG may be 0.992 vs 0.997). Now, where I'm going with this is that all we are observing with our FG readings is a number like 1.010 but the starting point is different. So the high gravity brew might have enough nonfermentable sugars to go from .992 to 1.010 (18 pts) but the session beer might only have enough to go from .997 to 1.010 (13 pts). Sooooo . . . this means that TwoHeads is absolutely right! There probably is more sugary sweetness left in this moderately high gravity beer he brewed than many of his other beers with a similar FG.

That's a long hypothesis. Hope it makes sense. The numbers are made up, though I'm sure there must be a way to quantify this correction -- just don't have the time atm to figure it out.

Ok, that makes sense. You're saying that alcohol content actually screws up the hydrometer because it has a gravity lower than pure water? If that is the case, we need some sort of conversion utility to adjust for alcohol content. A 1.010 beer with 4.5% alcohol is actually going to have less unfermentable sugars than a 1.010 beer with 7.0% alcohol. Am I hearing you right?

TwoHeadsBrewing said:

Ok, that makes sense. You're saying that alcohol content actually screws up the hydrometer because it has a gravity lower than pure water? If that is the case, we need some sort of conversion utility to adjust for alcohol content. A 1.010 beer with 4.5% alcohol is actually going to have less unfermentable sugars than a 1.010 beer with 7.0% alcohol. Am I hearing you right?

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That is exactly right! Both beers with a 1.010 FG will have the same objective "thickness" compared to water but that will be caused by a different combination of residual sugars and alcohol in the 4.5% and 7% alcohol beers with there being more sugars in the 7% beer.

Just as an aside, the fact that alcohol is lighter than water is also why our alcohol by weight and alcohol by volume measures differ with abv always higher -- because alcohol is lighter in weight (thus lower in gravity).