Lower than expected final ABV from kits

[Bertiebert]

Hi, please somebody tell me I'm wrong here.
I've done three beer kits thus far. Each one has an advertised ABV between 4.3 -4.7% yet I've had to add sugars each time to get anywhere close to this.
The latest kit is a Saint Peter's ruby, it's advertised but 4.3 ABV. Once I thoroughly mixed the wart I took a gravity reading. It was very low, around 1.035. now if this was to ferment down to 0.000 (I know it can't) it would give about 4.5% ABV. If we assume it ferments down to 0.010 it would only yield 3.3%ABV. If my calculations are correct this is considerably less than the advertised 4.3%?
Anyway I've ended up adding 500 grams of dextrose to bring the ABV up to 0.044. If this ferments down to the given 0.010 it should give me a beer of 4.5% right?
If I'm right why is the ABV on the kit so low?
If I'm wrong then please somebody put me right.
Thanks,

 

[The Drunken Spaniel]

Hi, please somebody tell me I'm wrong here.
I've done three beer kits thus far. Each one has an advertised ABV between 4.3 -4.7% yet I've had to add sugars each time to get anywhere close to this.
The latest kit is a Saint Peter's ruby, it's advertised but 4.3 ABV. Once I thoroughly mixed the wart I took a gravity reading. It was very low, around 1.035. now if this was to ferment down to 0.000 (I know it can't) it would give about 4.5% ABV. If we assume it ferments down to 0.010 it would only yield 3.3%ABV. If my calculations are correct this is considerably less than the advertised 4.3%?
Anyway I've ended up adding 500 grams of dextrose to bring the ABV up to 0.044. If this ferments down to the given 0.010 it should give me a beer of 4.5% right?
If I'm right why is the ABV on the kit so low?
If I'm wrong then please somebody put me right.
Thanks,

Hi there,

Kit brewing is not my forte I’m afraid but, as no one has replied yet, I’ll try a couple of pointers. I believe that the low SG readings can only be due to one, or both, of the following.

1. Over dilution - you could try adding half of the water and taking a reading. Depending on that reading you could either add more water, taking more readings or, given your first reading, using an online calculator to determine how much more water is needed to bring your particular volume to the desired OG figure.

2. Temperature at which you take the reading. This won’t have such a dramatic effect but should always be considered.

You don’t say what you are using to measure the SG. If it’s a refractometer it will need calibrating to start. If a hydrometer, make sure the sample is at 20 c and it is not “sticking” to the side of it’s jar.

I have made wine from kits and their claims to be “ready in 3 weeks” are always optimistic, perhaps beer kits are equally truthful?

Hopefully this helps but I’m all grain, so this is out of my comfort zone.

All the best

Cheers.

 

[Bitter_Dave]

You should not be getting low starting gravities like that. Malt extract is incredibly consistent in that regard.

Some things to consider:

Is the malt extract mixed enough? Some can linger at the bottom of the fermenter and lead to an inaccurate reading at the top. It should still ferment ok though.

Are the volume markings on the fermenter accurate? On mine they are not and if you rely on them you add too much water. It's worth checking them.

 

[Laner]

Each of the kits I’ve brewed, so far, have sugar required in the instructions ( or brew enhancer ).