Attenuation

[Maricel]

I have just made my first batch of ginger beer.

Using the Brewers Friend website ABV calculator I entered my initial sg reading and my intended final sg.

The calculator has a field called: Apparent Attenuation and the value is a percentage.

How does this number relate to the final sweetness/dryness of the brew? Does it mean the lower the percentage the sweeter?

If so, what should I be aiming for, as a percentage, to have something a little sweet, but not sickly sweet?

Ta

 

[Hazelwood Brewery]

Attenuation is a measure of how much sugar has been converted to alcohol so the higher the attenuation the more fermentable sugar is converted to alcohol.

My use of the word fermentable is deliberate because there are also unfermentable sugars (eg lactose) that will remain unfermented and can be added for extra sweetness if you wish.

I’m afraid I’m not an expert in ginger beer so not sure what you might aim for (and this is also a matter of personal taste) but 1.01 as a finishing gravity is not especially sweet in an ale.

Given that this is your first batch, maybe go with it and make adjustments if needed next time once you know how it turns out.

Edit: If you make it and want it sweeter you can still add lactose (assuming you’re not lactose intolerant!).

 

[DocAnna]

The attenuation percentage will depend on the yeast used which is dependent on the type of sugars the yeast can metabolise and it's tolerance of alcohol and other metabolites. The reason it is 'apparent' is that it relates to the difference between original and final gravity as measured with a hydrometer, and the final gravity is lower than just removing the sugar would cause, due to the alcohol being lighter than water and so making the liquid look like more of the sugar has been consumed.
So an apparent attenuation of 75% would at first look suggest the yeast digests 75% of the sugars but its actually a much smaller percentage, it's just that the alcohol makes the final liquid look lighter than it would be then if the sugars within water.

The short version is a high Apparent attenuation will give you a drier taste providing that you aren't making something that exceeds the alcohol tolerance of the yeast. A lower percentage will leave more unfermented sugars and more 'mouthfeel', oh and to complicate things, as @Hazelwood Brewery says, some sugars can't be digested at all so don't count in this, but that is unlikely to apply to ginger beer. I hope that makes sense.

Sweetness is a function of attenuation, unfermentable sugars, and if you've exceeded the alcohol tolerance of the yeast sugars will remain as well.

Anna

 

[Maricel]

Thank you both for your very useful replies. I now have a much better understanding of that parameter.

Do either of you have any idea of a suitable fermentation temperature for ginger beer?

I live on a sub tropical island and temperatures are around 30C at the moment. I have an old chest freezer that I have attached an alternative thermostat to. It's currently hovering around the 18C mark.

I kicked off the ginger beer about 4 hours ago and it's already bubbling quite vigorously.

Any more advice would be gratefully received.

Ta

 

[Hazelwood Brewery]

Again, I’m no expert in ginger beer but the yeast will determine the best temperature so you might want to check the yeast packet?

 

[Maricel]

Unfortunately, there are no clues on the packet as I'm using bread yeast.

 

[DocAnna]

Unfortunately, there are no clues on the packet as I'm using bread yeast.

Ah then I'd go for a rough 75% estimate of attenuation, might go as high as 80% though. Alcohol tolerance is going to be a bit random though, which is more likely to influence the sweetness, could be as low as 3.5% or as high as 14%. Essentially with a bread yeast you're in experimental territory.

 

[Hazelwood Brewery]

Unfortunately, there are no clues on the packet as I'm using bread yeast.

In that case use the temperature you normally prove your bread at!

 

[DocAnna]

Thank you both for your very useful replies. I now have a much better understanding of that parameter.

Do either of you have any idea of a suitable fermentation temperature for ginger beer?

I live on a sub tropical island and temperatures are around 30C at the moment. I have an old chest freezer that I have attached an alternative thermostat to. It's currently hovering around the 18C mark.

I kicked off the ginger beer about 4 hours ago and it's already bubbling quite vigorously.

Any more advice would be gratefully received.

Ta

Have you considered ordering a Kveik yeast online - keep some from a simple starter or top crop and keep using it again and again. That way you could ferment at room temperature.

 

[Maricel]

In case anyone is interested, this is my recipe and process. I'll check back in in a couple of weeks with an update.

Ginger wine​	​	27/05/21​	​	Start Time: 9:30 PM​	​
​	​	​	​	​	​
​	​	​	​	​	​
Water​	4L​	​	​	​	​
Brown sugar​	1000g​	​	​	​	​
Raw ginger​	200g​	​	​	​	​
Lemon Juice​	50g​	​	​	​	​
Bread Yeast​	12g​	​	​	​	​
​	​	​	​	​	​
Boil 4 litres of water. Add sugar, lemon, and blended ginger. Simmer for 45 minutes​	​	​	​	​	​
​	​	​	​	​	​
Cool to room temperature and strain ginger.​	​	​	​	​	​
​	​	​	​	​	​
Add to 5L water bottle​	​	​	​	​	​
​	​	​	​	​	​
Add a packet of bread yeast (12g)​	​	​	​	​	​
​	​	​	​	​	​
Top up with pre-boiled cold water to 5L​	​	​	​	​	​
​	​	​	​	​	​
Ferment at 18C for 7 days​	​	​	​	​	​
​	​	​	​	​	​
Add 1/2tsp of white granulated sugar to 330ml bottle and cap​	​	​	​	​	​
​	​	​	​	​	​
Starting SG​	1.06​	​	​	​	​
​	​	​	​	​	​
Finish SG​	1.02​	​	(Expected)​	​	​
​	​	​	​	​	​
Attenuation​	83%​	​	​	​	​
​	​	​	​	​	​
ABV​	6.50%​	​	​	​	​

 

[RoomWithABrew]

@Maricel
I've made a couple of ginger beers now. Given that your fermentable is sugar I'd expect this to go to 1.000 which will be 100% attenuation.

Might not get there if the bread yeast can't cope with the alcohol. I've used kveik and champagne yeast and both gone to 1.000

I lob the ginger in the fermenter. You might find that a week isn't long enough for that ferment. Don't bottle before ferment is over and add more sugar you will get bottle bombs.

You need to measure the gravity when the ferment is finished to calculate the ABV not based on guess.

If it's near 1.000 it will be dry, you'll need to back sweeten the bottles with an artificial sweetener like Erythritol or monk fruit extract for a non artificial tang.

I've started to use LME and some grain steeping to try and put some body in the ginger beer as really the sugar recipes are ginger seltzers. Which might be what you want.

 

[user 41945]

I'm just starting with ginger beer but 1kg of sugar seems a lot in 5l. I'm using 500g and I have a start SG of 1046 (in about 4.5l) which I'm expecting (unless I've done my sums wrong) to end up around 4.5 to 5% ABV, yeast permitting.
I'm using a wild yeast from a ginger bug and temperature is 18 to 20C pending the alleged arrival of summer. Still gently bubbling after 3 weeks.

 

[RoomWithABrew]

@malcolmbebb
I admire your patience, after a good boil of the ingredients and a beer or wine yeast you could be drinking it and improving your recipe in a fortnight or so.

 

[Stu123]

This worked for me:
Alcoholic Ginger beer
16 feb 2021
1 kg ginger peeled and grated
6 tsp ginger powder
2 tsp cream of tartar
2 lemons and 2 limes
5 green chillies
2.5kg sugar
Yeast nutrient
Sweetened yeast from cider kit
Boil grated ginger, powder ginger, CoT sliced juiced lem n limes for half an hour.
Add sugar bring up to boil.
Transfer-to fv
Made up to 4 gall.
added yeast nutrient and yeast.
didnt note but i think the og was about 1045 ish.

this fermented down to 1.005 in about 3 weeks.
bottled with 10g per litre sugar
result was really nice and spicy with enough fizz to go up your nose!,
think i’ll reduce the number of chillies by half next time!

i also bottled some in champagne bottles primed at 20 g per litre and did method traditional to get rid of the yeast.

 

[Maricel]

I see that cream of tartar is often used, why? Can I add this at the end of the ferment as I wasn't aware I needed it when I started the fermentation?

 

[Stu123]

I see that cream of tartar is often used, why? Can I add this at the end of the ferment as I wasn't aware I needed it when I started the fermentation?

Apparently it helps with the “mouth feel” ive made it in the past without and it was lacking in body. I put it in the boil. ( chillies as well)
the sweetened yeast( from a bulldog cider kit) also helped based on previous brews.

 

[RoomWithABrew]

I saw somewhere that they used the liquid from a mug of stewed tea one teabag only to improve the mouthfeel. For the tannins I suppose. Not tried this myself.