Coopers IPA kit and gravity calculations

[Stavrogin78]

Hi folks,

I'm still fairly new to doing these kits, but I did one a while back and while the result was not bad, I found I didn't hit the OG that I'd figured on, and I'm wondering why.

This was a 23L batch, and here's what went in, together with how I did my calculations:

3.75lb Coopers IPA extract, 36PPG (135)
2lb Briess Golden Light DME, 43PPG (86)
.8lb Dextrose, 46PPG (37)

135+86+37=258, divide by 6 gallons, gives 43. So I figured OG would have been around 1.043. What I got was about 1.040, dropping to 1.009 when I racked it to the carboy eight days later, for about 4.1% ABV, which was a little light.

Did I go wrong somewhere? I'd like to bring that OG up a little this time around. The DME and the dextrose are what I've got at my disposal. Would adding some more DME do the trick here?

Thanks in advance for any advice!

 

[BrewnWKopperKat]

Did I go wrong somewhere?

What was the volume of your wort? OG 40 in 6.5 gal water is 260 gravity points.

I'd like to bring that OG up a little this time around. The DME and the dextrose are what I've got at my disposal. Would adding some more DME do the trick here?

From a simple math perspective, adding a lb of DME will add 7 GPs in 6 gal of wort.

Adding small amounts (8 to 16 oz) of DME probably won't require changes in hop amounts. With larger changes in malt amounts, I'd look into changing the amount of hops used as well.

 

[IslandLizard]

Did you leave any wort behind in the kettle, IOW, wort that didn't make it into the fermenter?

Did you do a partial boil with top up, or a full boil?

 

[Stavrogin78]

Wort volume was 23L right on. Should have been an even six gallons.

So even adding a half pound of DME should bring that up by 3.5, I guess. That doesn't sound extreme at all. I'm not messing with hops or anything yet, I'm still keeping things pretty basic. The closest homebrew supply store is a two hour drive away, so I'm just working with what I've got here.

I'm still trying to figure out if I did something wrong with my initial calculations, though, that resulted in my OG not being what I expected.

 

[Stavrogin78]

Did you leave any wort behind in the kettle, IOW, wort that didn't make it into the fermenter?

Did you do a partial boil with top up, or a full boil?

Everything went into the fermenter. And I just sort of followed the kit directions; put 3L of water in a pot, brought it to a boil, added the DME and dextrose, simmered for 15 minutes, turned off the heat and added the can contents (I used a little bit of boiled water to get all the extract out of the can). Mixed it up, then put the pot in an ice bath to cool it. Poured it into the primary, topped up to 23L with water, got it to 22C, and pitched the yeast.

 

[IslandLizard]

Everything went into the fermenter. And I just sort of followed the kit directions; put 3L of water in a pot, brought it to a boil, added the DME and dextrose, simmered for 15 minutes, turned off the heat and added the can contents (I used a little bit of boiled water to get all the extract out of the can). Mixed it up, then put the pot in an ice bath to cool it. Poured it into the primary, topped up to 23L with water, got it to 22C, and pitched the yeast.

Sounds like you did everything right there.

Have you ever calibrated your hydrometer? 1.000 with distilled water and 1.040 with a sucrose solution? To get exact numbers, temp is important, most are calibrated at 60F.
So, either read at 60F or use a correction formula for different temps.

Just a hint for later, there is no need to rack/transfer into a "secondary." Leave the beer where it is until ready to package.

 

[Stavrogin78]

Just a hint for later, there is no need to rack/transfer into a "secondary." Leave the beer where it is until ready to package.

Does it do any harm to rack it into a carboy? I have kids and dogs, and no lid for my primary. During primary fermentation, the beer just sits with a towel over the top to keep bugs and dust out, but it's kinda vulnerable. Racking to the carboy puts it in a much safer place.

And thanks for the tip about the hydrometer. Did not know that!

 

[IslandLizard]

Does it do any harm to rack it into a carboy? I have kids and dogs, and no lid for my primary. During primary fermentation, the beer just sits with a towel over the top to keep bugs and dust out, but it's kinda vulnerable. Racking to the carboy puts it in a much safer place.

And thanks for the tip about the hydrometer. Did not know that!

I prefer fermenters I can put a lid on, nice and tight, with an airlock, such a brew bucket. That way the headspace will become filled with CO2 from fermentation, which protects the beer from intruders and air (oxygen). When you rack from your basically "open fermenter" to a secondary (your carboy) while the fermentation is still fairly active, but the big event is over, and put an airlock on it, the headspace will again fill with CO2. Then all is good, yes!

Air (oxygen) exposure, can and will cause beer to oxidize, so try to prevent that from happening as much as you can. This becomes more important with hoppeir beers, which are really sensitive to oxidation.