Does Lactose Ferment At All?

[chillihilli]

Hi there, I've just bottled my new ginger beer "MyThai". Heres the recipe:

1 x Lime
2 x Kaffir Lime Leaves
2 x tsp coriander seed cracked
150 G raw ginger peeled
1 inch cube raw galangal root
2 tsp vanilla extract
125G corn syrup
125g lactose
250g dried malt extract

Blend it up
boil in 2L water
blend on the stove with a bamix
then simmer for 20 mins and make up to 10L (fermented in a supermarket 10L water container).
Coopers Pale Ale yeast

FG was 1010

Early indications look good, but it wasn't sweet enough so I boiled up an extra 375g of lactose and added it prior to bottling.

It seems to be gassier than usual, so my question is Does the lactose ferment at all?

I'm now concerned I'll have exploding GB's in the family room. Fortunately they are bottled in PET - except for 1. I have already let some gas out, but am wondering how cautious I'll have to be.

 

[razz]

It's non-fermentable chillihilli, just not exactly sure if that means 100%.
Perhaps crack a bottle every two weeks and see if you get to much head ( as if that's possible)

 

[Scruffy]

Couple of things that ferment Lactose.

E.coli and Salmonella. Good Luck!

 

[Pete2501]

Lactose - A nonfermentable sugar, lactose comes from milk and has historically been added to Stout, hence Milk Stout.

Link

Edit: The above is within the context of brewing. As Scuffy points out it can be fermented but in your case.. you don't want that <_<

 

[peas_and_corn]

Yeah, it won't ferment, so it'll be somewhat sweet. I'll be interested in hearing how the recipe will go, sounds interesting.

 

[chillihilli]

Yeah, it won't ferment, so it'll be somewhat sweet. I'll be interested in hearing how the recipe will go, sounds interesting.

Great, thanks to all for the advice. I just wasn't sure if there would be a small % of lactose that would ferment and add to my carbo levels.

Regarding the recipe, the next one I do will not have a full lime. The sourness is coming through. The galangal root is the real stand out. It add's a subtle musty,smokey root element the flavour and aroma. I will defnitely include that in the next batch.

 

[chillihilli]

Couple of things that ferment Lactose.

E.coli and Salmonella. Good Luck!

Definitely not planning any of those! I do sanitise my gear and bottles :icon_vomit:

 

[Snow]

Lactose ferments just fine in my gut! Last time I make a milk stout <_<

Cheers - Snow

 

[drsmurto]

I realise why people add lactose to ginger beers and ciders but what almost everyone fails to take into account is the fact that lactose is only 20% as sweet as sucrose.

Some back of the napkin calculations for you since its lunch and I'm bored.

Bundaberg Ginger Beer contains ~10g of sugar per 100mL or 100g/L.

That's 2kg in 20L.

Assuming that's a simple sugar such as sucrose and since you need 5 times as much lactose to achieve the same relative sweetness you would need 10kg of lactose in a 20L batch.

This makes a lot of assumptions, the biggest being the nature of the sugar in Bundy GB (and the fact people want to get even close to the sweetness of Bundy GB)

Other examples if you want to judge sweetness are powerade at 60g/L, coke at 100g/L and fanta at 130g/L.

Food for thought.

Cheers
DrSmurto

p.s. re-reading this i have this nagging feeling i have make a glaring error in this calculation as 10kg is crazy talk. Feel free to pick holes in my calculations.

EDIT - the enzyme 'lactase' is needed to break lactose down into glucose and galactose before yeast can convert it into ethanol and CO2. This enzyme is reportedly used to produce lactose free milk.

 

[Pete2501]

Yeah I was getting Melibiose and galactose confused.

 

[Thirsty Boy]

I dont think you are too far off Dr S - put a spoon of lactose in your mouth. Not exactly a sweetness explosion.

My understanding is that is primarily used in things like milk stout to add body and reduce "dryness" - which it can do perfectly well without being sweet. Mind you, about a 5th as sweet as commercial soft drink sounds about right to me.

 

[chillihilli]

I realise why people add lactose to ginger beers and ciders but what almost everyone fails to take into account is the fact that lactose is only 20% as sweet as sucrose.

This makes a lot of assumptions, the biggest being the nature of the sugar in Bundy GB (and the fact people want to get even close to the sweetness of Bundy GB)

You have hit the nail on the head. I don't want anywhere near the sweetness of Bundy. Whilst I love it, it's way too sweet for me (and I give it to the kids so always try and reduce their sugar intake where possible).

My last GB's i only used sugar for fermentation, and they were not sweet at all. The downside, which is also to Thirsty Boy's point, is that they come out very dry and the last one was way too watery. That said, the kids and I still like it, and being low on sugar and fizz it's a great hot day refresher (kind of like a ginger flavoured water). We are certainly making our way through the 25L batch that I made!

So this time 'round, I added corn syrup and lactose to give more head (prolly explains the extra fizz) and lactose to sweeten it up again. I dropped the batch size to 10L so I could both experiment and make it more syrupy/stronger.

Slightly off topic, but one thing I have noticed with Ginger Beer is it really highlights the value of bottle conditioning. What tastes very ordinary 2 weeks after bottling continues to ferment slightly and develops a lot of complexity. Also notice the longer they bottle condition the gassier they are, which tells me that the fermentation is still slowly ticking along. I usualy give them about 7 - 9 days in the fermenter and wait for consistent FG readings over 24 hrs.

 

[superdave]

I realise why people add lactose to ginger beers and ciders but what almost everyone fails to take into account is the fact that lactose is only 20% as sweet as sucrose.


p.s. re-reading this i have this nagging feeling i have make a glaring error in this calculation as 10kg is crazy talk. Feel free to pick holes in my calculations.

I do my ginger beers with a malt base so there is residual sweetness from the unfermented sugars.
I no longer add lactose as you pointed out it doesn't change the sweetness by much.