Substituting dark molasses for LME in Irish Stout

I'm in the planning phase of an Irish Stout. One recipe I'm using calls for Pale LME. However, I'm always looking to change things up a bit.

Is it a crazy notion to substitute the 3 lbs of LME with 3 lbs of dark molasses?

I realize the color would be affected. However, would the boil take most of the molasses flavor out and simply use it for sugar like LME, or would there be some residual molasses flavor left? Either would be fine with me, I'm just curious.

T

Molasses is the end product of a crazy amount of boiling, so I highly doubt a little more is going to alter the flavor much. That's a lot of molasses, so expect the flavor to carry over into the beer significantly. Look to the amount of sugar to give you an idea of what degree of fermentability to expect. I have no idea what the overall gravity impact would be.

I am assuming that this is a 5 gallon batch? If so than I wouldn't use all 3# of the molasses. A little goes a long way, maybe cut it down to a pound or pound and a half. Too much can cause the beer to be overly sweet, covering up the other subtleties that you want in a stout. The dark molasses like blackstrap contains about 50% fermentables

tally350z said:

Too much can cause the beer to be overly sweet

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I must say I haven't used much molasses in brewing before, but too much makes for a sweet beer? What is it about molasses that you think/know will make the end product sweet? I'm not saying you're wrong, I'm just very surprised to hear this (and maybe a little skeptical).

Well specifically it is the dark molasses, which contains only 50% fermentables meaning the more use(higher % of total) the more unfermentables you will have in the beer. The max percentage for the dark is at 5% and if he is thinking of using 3 lbs, not knowing what the entire recipe is I would think that it will be somewhere between 40-50& of the batch. The regular molasses is ok to use in higher percentages because it is 90% fermentable.

I haven't ever looked into this, but it's an issue with honey for mead, molasses may be very low in the nutrients that yeast need for a healthy fermentation (regardless of sugar fermentability). If so, make sure to account for that with a good staggered dosing of the proper nutrients.

tally350z said:

Well specifically it is the dark molasses, which contains only 50% fermentables meaning the more use(higher % of total) the more unfermentables you will have in the beer.

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Unfermentable stuff, yes. I'm with you there. But why would all that remaining stuff be sweet? That's where you're losing me.

Well specifically in this situation he is trying to make an irish stout, which are typically dry, rather than sweet. Without knowing the rest of the recipe I don't know, but thats what I was assuming.

tally350z said:

Without knowing the rest of the recipe

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This is the primary point, no doubt. We don't have a recipe, so we can't guess at the overall impact.

However, with regards to the molasses, if the sugars ferment out, there's not much left to be sweet. Maybe there are some longer chained sugars that are slightly sweet, yet unfermentable to brewer's yeast, but I doubt that would be a large portion of what's left. You might get a slightly heavier body, perhaps, with such a high amount of unfermentable stuff, but I'm doubting very much it would taste sweet. Maybe it wouldn't even affect the body much. I guess it depends what's left over after fermentation.

GuldTuborg said:

This is the primary point, no doubt. We don't have a recipe, so we can't guess at the overall impact.

However, with regards to the molasses, if the sugars ferment out, there's not much left to be sweet. Maybe there are some longer chained sugars that are slightly sweet, yet unfermentable to brewer's yeast, but I doubt that would be a large portion of what's left. You might get a slightly heavier body, perhaps, with such a high amount of unfermentable stuff, but I'm doubting very much it would taste sweet. Maybe it wouldn't even affect the body much. I guess it depends what's left over after fermentation.

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I have no personal experience or knowledge concernng the subject, but the discussion piqued my interest. So I went to Google and found a site about producing alcohol from cane, which states "...it is clear that about 52.5% of the brix in molasses are fermentable sugars."

http://www.sugartech.co.za/alcohol/molasses.php

Seems to me that leaves room for a lot of unfermentable sugars, which could significantly sweeten the final beer..... But again, I'm no expert.

OP can you post the entire recipe? So we can see the direction you want to take with the overall beer..

It all depends what's left. The darker the molasses, the less simple sugars it has. We know that, and it's reflected in its fermentability at different levels. Going by this, we also know there's no meaningful amount of fat or protein, either.

So where is the gravity coming from? Well, roughly 75% of the carbs in molasses are classified as sugars. I'm guessing that other 25% is not sweet. So roughly 2/3 of the sugars ferment, say, which leaves 25% of the original carb amounts as possibly and slightly sweet, but unfermented. That's if all the relative densities are the same, which of course they may not be.

There also seems to be a pretty high level of salts and other minerals, and more the darker the molasses gets. That will have a measurable effect on gravity, if slight. There will be about 2oz of ash per 3lbs of molasses. I don't know if that will all remain in suspension (my guess is it mainly will, but I don't know), but if so, that's just more gravity that's not sweet.

I guess my point is, there's a lot of stuff in the remainder of the gravity that's definitely not going to be sweet. There's also a good amount that is, and may be. But on a significantly greater scale than malt extract? I don't know, and maybe I'm just crazy, but I don't think the answer is in any way clear one way or the other.

I guess someone will just have to try it and report back.

Recipe (given the amt off molasses is still debatable) started from the book "Classic Beer Style Series" on Stout. The original recipe was a full mash. I tend to do mostly partial mashes or extract w/grains. So, after researching "substituting LME for grains" in a couple of booksand on the internet, I estimated the amount of LME (not molasses) to use to substitute some of the Pale Two Row malt.

1 lb Pale Two Row Malt
17.5 oz of Flaked Barley
12 oz. Roasted Barley
8 oz of Chocolate Malt
3lbs of Pale LME (or 1.5-3 lbs of molasses)
2 oz. Kent Goldings
WLP004 Irish Yeast

Recipe started from the book "Classic Beer Style Series" on Stout. The original recipe was a full mash. I tend to do mostly partial mashes or extract w/grains. So, after researching "substituting LME for grains" in a couple of books and on the internet, I estimated the amount of LME (not molasses) to use to substitute some of the Pale Two Row malt.

1 lb Pale Two Row Malt
17.5 oz of Flaked Barley
12 oz. Roasted Barley
8 oz of Chocolate Malt
3lbs of Pale LME (or 1.5-3 lbs of molasses)
2 oz. Kent Goldings
WLP004 Irish Yeast