Swapped Dextrose for LME - Low Alcohol

[Ciaron99]

I started a NZ Pilsner from a kit. I heard its better to use LME instead of regular sugar and was a little heavy handed with the LME as it was 1.5kg pouch and not the 1.2 recommended for the Pils. So 11 days later and my readings look like my beer is around 2.5% alcohol, way off the 4.4% on the box. It hasn't reached the advised FG yet but not sure if this is because of the extra LME.

Have I done something wrong? Does LME produce less Alcohol?
If it stays the same could I add sugar at this stage to up the alcohol level?

Thanks in advance.

 

[beerlife]

I would need some more info on the kit as I not familiar with it at all. What all did you add?

 

[Ciaron99]

I added the NZ Pilsner Malt Extract Kit, The Pure Liquid Malt Extract, Yeast and water. The kit has a section recommending either 1.2 kg of LME or 1kg of dextrose. So I went with about 1.3kg of the LME.

 

[beerlife]

How much is the total volume of beer? what was the OG when you made the beer?

 

[Ciaron99]

23 Liters, the OG gravity was 1.038. The box says FG should be 1.006 but currently its 1.018 and steady.

 

[beerlife]

Does the box's recipe state final volume of 23 liters?

anyway, so seems like you had way too little malt in your brew. I would not add any sugars. I in fact never put sugar in my beers. to be honest, I would not really mess with it, perhaps just accept it as is and consider it a light beer.

 

[Ciaron99]

Does the box's recipe state final volume of 23 liters?

Yep

 

[beerlife]

Do you have any links to this specific kit perhaps, please?

 

[Ciaron99]

Do you have any links to this specific kit perhaps, please?

https://www.geterbrewed.com/mangrove-jacks-new-zealand-brewers-series-pilsner-blonde/

 

[VikeMan]

Does LME produce less Alcohol?

By weight, yes. Very roughly, LME contributes about 83.7% as much original gravity as dextrose.

Next, the sugars/dextrins in LME are not fully fermentable. (How fermentable depends on the yeast strain.) Let's say 75% fermentable in your case. Dextrose, on the other hand, is 100% fermentable, regardless of yeast strain.

So that's 83.7% x 75% = ~63%

i.e. the LME would produce roughly 63% as much alcohol as the same weight of dextrose.

You added 1.3 kg of LME, which would then be equivalent to 1.3 Kg x 63% = 0.82 kg of dextrose.

Without belaboring the math any further , I'd estimate that using 1.3 kg of LME instead of 1 Kg of dextrose reduced your ABV only by something less that than 0.5%, so there's something else going on.

Are you using a hydrometer or a refractometer?

 

[Ciaron99]

Hydrometer.

Could some unwanted nasty bacteria be affecting the yeast? Would that explain it?

Its been at 22-24˚C since the yeast was added so I'm not concerned about temperature.

 

[VikeMan]

Could some unwanted nasty bacteria be affecting the yeast? Would that explain it?

Unlikely. The beer would have to get pretty sour (low pH) before the yeast would be slowed.

You say OG was 1.038. Is that close to what the kit called for? If not, was this a "top off with water after the boil" recipe, and did you make sure to mix the wort and top off water thoroughly before taking the OG sample?

And, was your actual volume really the same as the recipe's volume?

 

[Ciaron99]

The Kit didn't give what the OG should be, just the FG.

You say OG was 1.038. Is that close to what the kit called for? If not, was this a "top off with water after the boil" recipe, and did you make sure to mix the wort and top off water thoroughly before taking the OG sample?

And, was your actual volume really the same as the recipe's volume?

Yep, I topped off with cold water to get it to 24˚C, gave it a good stir, took the sample, added my yeast and stirred again.

 

[Yooper]

So, you used 1.7 kg of malt from the kit, and 1.3 kg that you added, for a total of 3 kg of malt extract in 23L? If so, the OG of the wort would be 1.041. It has to be- because the sugar is a set amount. Your OG reading was very close, but maybe you had a little more water in that particular sample or maybe you added a touch more water than the 23L exact volume.

The current SG is a bit high for finishing, though.
The formula for estimating the ABV is (Og-Fg) x 131= % ABV
So right now you are sitting at 3%.
It's a little low for two reasons. First, 1.041 is an OG for a fairly light beer. With only 3 kg of fermentables in a 23L batch, you just won't get a 6% beer of course.
Secondly, the yeast pooped out before fermenting it as low as desired, generally 1.010 or so.

It may go lower, but if not, a nice tasty 3% ABV beer is better than one boosted with sugar that would thin the beer and dry it out (but produce alcohol).

 

[Ciaron99]

It's a little low for two reasons. First, 1.041 is an OG for a fairly light beer. With only 3 kg of fermentables in a 23L batch, you just won't get a 6% beer of course.
Secondly, the yeast pooped out before fermenting it as low as desired, generally 1.010 or so.

I wasn't expecting it to get to 6% but presumed it would hit the 4.4% on the box.
So just put this one down to some dodgy yeast and hope for better in the future?

 

[Yooper]

I wasn't expecting it to get to 6% but presumed it would hit the 4.4% on the box.
So just put this one down to some dodgy yeast and hope for better in the future?

Could be dodgy yeast, but I think it's more likely that the extract is less fermentable (and better for the body and flavor of the beer!) than sugar. Or the extract was slightly older and not as fresh as it could be, especially if it was canned and not fresh from an argon flushed bulk container.

If the ABV is more important than the quality, you can always add the sugar.

Don't forget that adding sugar to the beer to bottle carbonate will add about .5% ABV also.