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Complete HomeBrew Noob.

245

Comments

  • Closed Accounts Posts: 2,923 ✭✭✭cloptrop


    BeerNut wrote: »
    FG= Final Gravity.
    OG= Original Gravity
    SG is any gravity in between.

    ...you'd be a billionaire!
    or jesus


  • Moderators, Society & Culture Moderators Posts: 9,689 Mod ✭✭✭✭stevenmu


    cloptrop wrote: »
    but isnt the specific gravity directly related to the weight , say for example a litre of water weighs a kilo , if you made alcohol from water and then weighed a litre of it and it was 1 and a half kilo would the specific gravity be 1.5?
    i remember something like this from plumbing school , could be mashing two formulae together though , it was a while ago.

    I could be wrong on this but my understanding is that the specific gravity is basically a measure of the density of the liquid. The hydrometer is basically just a float with levels marked on it. The denser the liquid the higher the hydrometer will float, and the less dense the liquid the lower the hydrometer will float, and you can use the markings on the hydrometer to measure this accurately.

    Water on it's own has a specific gravity of 1.000 (more or less). Adding sugars/malts to water causes it to be more dense, causing the hydrometer to float higher, in turn giving a higher SG, for e.g. 1.060. The yeast ferments this sugar/malt converting it into CO2 which is less dense than water and most of it escapes, and alcohol, which I believe is also less dense than water (but even if it isn't the escaping CO2 means the liquid overall is less dense). Your liquid is less dense therefore the hydrometer will float lower in it, giving a lower reading, like 1.013 for e.g.

    In theory it shouldn't matter how much of the liquid you measure (as long as it's enough for the hydrometer to float in), because it's just the density of the liquid that you are measuring.



    edit: If you wanted you could then combine density and volume to get the weight, but that's not needed for beer making. You could also in theory use the weight and the volume to calculate the density and calculate the ABV from that which would be useful, but I'd guess that measuring the weight and volume accurately enough would be tricky.


  • Closed Accounts Posts: 2,923 ✭✭✭cloptrop


    stevenmu wrote: »
    I could be wrong on this but my understanding is that the specific gravity is basically a measure of the density of the liquid. The hydrometer is basically just a float with levels marked on it. The denser the liquid the higher the hydrometer will float, and the less dense the liquid the lower the hydrometer will float, and you can use the markings on the hydrometer to measure this accurately.

    Water on it's own has a specific gravity of 1.000 (more or less). Adding sugars/malts to water causes it to be more dense, causing the hydrometer to float higher, in turn giving a higher SG, for e.g. 1.060. The yeast ferments this sugar/malt converting it into CO2 which is less dense than water and most of it escapes, and alcohol, which I believe is also less dense than water (but even if it isn't the escaping CO2 means the liquid overall is less dense). You liquid is less dense therefore the hydrometer will float lower in it, giving a lower reading, like 1.013 for e.g.

    In theory it shouldn't matter how much of the liquid you measure (as long as it's enough for the hydrometer to float in, because it's just the density of the liquid that you are measuring.
    so are we saying the more sugar i put in the higher alcohol volume i will get?


  • Registered Users Posts: 4,431 ✭✭✭Sky King


    cloptrop wrote: »
    but isnt the specific gravity directly related to the weight

    It's kind of a misnomer. Specific Gravity is a measure if relative density, using water as a basis for compasiron.

    Water at 20 degrees C has a specific gravity of 1 - that's your starting point.

    Petrol for example has a specific gravity of 0.72 so you can see it's less dense than water.

    Sugars present in your fresh mix increase its density, so the specific gravity will be above 1. As these sugars are eaten by the yeast, they are depleted and the density is reduced.

    By taking a measure of the density of the liquid before and after fermantation, you can put a figure on the difference in density, and a simple formula will tell you how this figure relates to the percentage of alcohol in the liquid.

    A hydrometer works by virtue of the fact that an object will experience different levels of buoyancy in liquids of different density. Throw an aluminium washer into a jar of water, it sinks. Throw it in a jar of mercury, it floats. The hydrometer just maps this linear buoyancy variation onto a calibrated and readable scale


  • Moderators, Recreation & Hobbies Moderators Posts: 11,758 Mod ✭✭✭✭BeerNut


    cloptrop wrote: »
    so are we saying the more sugar i put in the higher alcohol volume i will get?
    Up to a point. If you're going for a high gravity wort you need to pick a robust yeast that can handle both the large amounts of sugar and all the alcohol that results.

    And for taste reasons it's best to get the sugar from malt rather than neat processed sugar.


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  • Closed Accounts Posts: 2,923 ✭✭✭cloptrop


    BeerNut wrote: »
    Up to a point. If you're going for a high gravity wort you need to pick a robust yeast that can handle both the large amounts of sugar and all the alcohol that results.

    And for taste reasons it's best to get the sugar from malt rather than neat processed sugar.
    so did i go wrong using table sugar


  • Moderators, Recreation & Hobbies Moderators Posts: 11,758 Mod ✭✭✭✭BeerNut


    You'll know when you taste it. If it's too thin and cidery: that's the sugar.


  • Registered Users Posts: 43 MR PIGGY


    BeerNut Please help.
    :confused:
    I am brewing coopers heritage lager using a can of 1.5kg can of ligth malt extract liquid that comes with it. This is going to sound silly but can you tell me that i am correct in thinking that the malt liquid is used in place of brewing suger/malt extract. Also will 18 DegC be ok for fermenting.


    Cheers


  • Registered Users Posts: 2,903 ✭✭✭DeadSkin


    MR PIGGY wrote: »
    BeerNut Please help.
    :confused:
    I am brewing coopers heritage lager using a can of 1.5kg can of ligth malt extract liquid that comes with it. This is going to sound silly but can you tell me that i am correct in thinking that the malt liquid is used in place of brewing suger/malt extract. Also will 18 DegC be ok for fermenting.


    Cheers

    From what I gather malt extract is used as an alternative to sugar & from here 18 degrees should be ok.


  • Registered Users Posts: 4,431 ✭✭✭Sky King


    DeadSkin wrote: »
    MR PIGGY wrote: »
    BeerNut Please help.
    :confused:
    I am brewing coopers heritage lager using a can of 1.5kg can of ligth malt extract liquid that comes with it. This is going to sound silly but can you tell me that i am correct in thinking that the malt liquid is used in place of brewing suger/malt extract. Also will 18 DegC be ok for fermenting.


    Cheers

    From what I gather malt extract is used as an alternative to sugar & from here 18 degrees should be ok.
    Dont coopers recommend usung their 'brew enhancer' too? Its basically just a kilo of dextrose.


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  • Moderators, Recreation & Hobbies Moderators Posts: 11,758 Mod ✭✭✭✭BeerNut


    MR PIGGY wrote: »
    I am brewing coopers heritage lager using a can of 1.5kg can of ligth malt extract liquid that comes with it.
    So you have the 1.5kg kit plus 1.5kg of liquid malt extract? That sounds like all the fermentables you need, so no need for any added sugar.


  • Registered Users Posts: 43 MR PIGGY


    BeerNut wrote: »
    So you have the 1.5kg kit plus 1.5kg of liquid malt extract? That sounds like all the fermentables you need, so no need for any added sugar.


    Thanks a lot BeerNut.

    One more thing if you dont mind, I saw is previous messages that you can add dried hops to the fermenter about a week before you bottle the brew. How do you do this(put in a bag or throw straight in) and what quantity of hops would you need.

    Cheers


  • Moderators, Recreation & Hobbies Moderators Posts: 11,758 Mod ✭✭✭✭BeerNut


    MR PIGGY wrote: »
    (put in a bag or throw straight in)
    You can do either: I generally throw straight in so they infuse more freely. Putting them in a bag means they're much easier to get out again so there's no risk of them clogging the siphon. Just make sure the bag is sanitised.
    MR PIGGY wrote: »
    and what quantity of hops would you need.
    That's a question of taste and variety. 20-30g of something like Cascade will do wonders.


  • Closed Accounts Posts: 2,923 ✭✭✭cloptrop


    Right ive been making inmate brew. I used a condom as an air lock. I was told it would take 3 weeks to be ready but the condom has deflated after a week and a half.This indicates the alcohol making process has ended. Has something gone wrong?
    When I shake it the condom fills again but I think this is just like shaking a fizzy drink because it goes back down. I have it in a room thats about 12 - 18 degrees all day and night .
    Did I just not put enough yeast in to make it work for 3 weeks?
    Did the lasting only a week and a half make the alcohol level smaller.
    I used orange juice , raisens yeast sugar .

    Should I just freeze it and hope for the best , or add more yeast and sugar . Maybe the fruitjuice just cant take anymore fermenting . I have no beer for the weekend , please dont make me go the off licence.


  • Closed Accounts Posts: 2,923 ✭✭✭cloptrop


    Anyone?


  • Moderators, Society & Culture Moderators Posts: 9,689 Mod ✭✭✭✭stevenmu


    cloptrop wrote: »
    I used a condom as an air lock.
    Wow, you're really dedicated to the authentic experience :)

    AFAIK condoms aren't air tight, so it probably takes a good bit of CO2 to keep them inflated. During initial fermentation a lot of CO2 is given off, but this will normally (for a regular beer anyway) slow down after a few days. It will still be fermenting, just at a slower rate, and giving off much less CO2. Your brew could still be working away and just not giving off enough CO2 to keep the condom inflated. If the recipe calls for 3 weeks, I'd be inclined to give it that long, even though it doesn't look active.


  • Closed Accounts Posts: 2,923 ✭✭✭cloptrop


    Lets say i stuck it in the freezer last night?
    Would i just get a far smaller alcohol volume or have i fecked it right up?
    Was working for a week and a half.


  • Moderators, Recreation & Hobbies Moderators Posts: 11,758 Mod ✭✭✭✭BeerNut


    You've probably killed the yeast. Ice crystals puncture the cell walls and they die.


  • Closed Accounts Posts: 2,923 ✭✭✭cloptrop


    But will alcohol have been already created but in a smaller amount , or will i just get loads of nearly made alcohol .
    eg the fermentation process only makes the alcohol on the third week.


  • Moderators, Recreation & Hobbies Moderators Posts: 11,758 Mod ✭✭✭✭BeerNut


    cloptrop wrote: »
    But will alcohol have been already created
    Yes.


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  • Closed Accounts Posts: 2,923 ✭✭✭cloptrop


    Cool I just have to figure out how to get rid of the scum out of the bottom


  • Registered Users Posts: 4,431 ✭✭✭Sky King


    Sounds delicious.


  • Registered Users Posts: 255 ✭✭Ronan cork


    i'm actually having a fantastic bottle of homebrew at the moment that a customer gave me and it's got me tempted to give it a try...the only thing im worried about is the smell as i live in an apartment and would have to keep it in my room and the door is usually closed...is anybody brewing in their bedroom and if so do your clothes etc smell like stale beer? would it be advisable or should i wait until i have a bigger place?
    thanks


  • Moderators, Recreation & Hobbies Moderators Posts: 11,758 Mod ✭✭✭✭BeerNut


    It doesn't smell. Well, some Belgian and cider yeasts can produce a bit of a pong for the first couple of days, but most don't. Certainly none of them leave a smell on anything.


  • Registered Users Posts: 19,491 ✭✭✭✭Krusty_Clown


    I'm about to bottle my second batch, and you wouldn't even know it was there, except for the occasional bubbling (which has woken me up the odd time, despite the fact that I brew downstairs and sleep upstairs (I'm a very light sleeper!).


  • Registered Users Posts: 255 ✭✭Ronan cork


    could i use an aquarium heater to keep a constant temp during fermentation? i've one for a 50L tank lying around. you can set the temp on it from 18-30


  • Moderators, Recreation & Hobbies Moderators Posts: 11,758 Mod ✭✭✭✭BeerNut


    Ronan cork wrote: »
    could i use an aquarium heater to keep a constant temp during fermentation?
    No idea. Why would you need that? Do you live in a greenhouse? Normal room temperature (17-22C) is perfect for ale fermentation.


  • Registered Users Posts: 255 ✭✭Ronan cork


    BeerNut wrote: »
    Ronan cork wrote: »
    could i use an aquarium heater to keep a constant temp during fermentation?
    No idea. Why would you need that? Do you live in a greenhouse? Normal room temperature (17-22C) is perfect for ale fermentation.

    Well no but I do like to air the place out every now and again! Was my understanding that a constant temp is very important so had been looking at brew belts and submursible heater things on the homebrew sites and they seem similar to aquarium heaters...


  • Moderators, Recreation & Hobbies Moderators Posts: 11,758 Mod ✭✭✭✭BeerNut


    Ronan cork wrote: »
    Was my understanding that a constant temp is very important
    Are you maybe thinking of wine cellaring? No such requirement for beer-making. Just don't let it get too warm, is all.

    People had been brewing beer for centuries before it was even possible to measure temperature, never mind keep it steady.


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  • Registered Users Posts: 849 ✭✭✭mayto


    Ronan cork wrote: »
    Well no but I do like to air the place out every now and again! Was my understanding that a constant temp is very important so had been looking at brew belts and submursible heater things on the homebrew sites and they seem similar to aquarium heaters...

    Brewbelts are good for keeping the beer from getting too cold, but you have to be careful it does not heat the beer too much either. Fermenting the the 18C to 20C region is usually an ideal range for most beers. If you ferment above 23C cecius you might get off flavours in the beer. I ferment in a wooden box with a lightbulb in it to genersate heat along with a temperature controller. A temp sensor is taped to one of the fermenters and the bulb comes on when it is too cold. During the summer I ferment in a fridge with a brewbelt around the fermenter.


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