Original Gravity Problems

[RichardG]

Guys, I recently purchase form Hamstead Homebrew their own make Santa's Special Sleigh Ride. Kit consists of a 3kg can of extract, a mixed bag of grains & hops for simmering, a 1kg bag of brewing sugar, and a packet of yeast. It's claimed to brew out to an ABV of some 6% and when speaking to them I was advised to expect an OG of around 1058 with a FG of 1014. Sounds great! Anyway, I had some problems. I've posted the message I sent them for your perusal;


'Chris,

As stated I put my Santa’s Special on last night and thought I’d give you an update.

I started by cleaning and sterilising all equipment then thoroughly rinsing. Whilst this was done I put the yeast in to rehydrate. I also used bottled water on this occasion. I usually just use tap water, but given the nature of the kit I decided to splash out; mine you at 15p per 2 Ltr bottle, it’s hardly extravagant!

The bag of mixed grains and hops was then put in a pan with 1 Ltr of cold water, brought to the boil then simmered for 20 minutes. At the same time the can of malt extract was placed in a pan of hot water to soften. Once the grains / hops were done, the malt extract was poured into the fermenting bucket and the cans rinsed out twice with boiling water to ensure all the extract was recovered. The grain / hop mix was then poured through a sieve into the bucket. The resultant grain / mix in the sieve were rinsed through with hot water once more, and this liquid also returned to the bucket. Meanwhile the bag of brewing sugar was placed in a pan with some cold water, and brought to the boil to minimise the risk of any infection getting into the wort via the sugar, and this mixture was added to the bucket. Having been topped up to 22 Ltrs total the wort was then given a good stir for 5 minutes or so to thoroughly aerate the mixture and then a sample taken to check the OG. At this point with the wort now cooled the rehydrated yeast was pitched, my heater connected up, and the whole lot moved to the under stairs cupboard to fermented. I’ve checked this morning and there’s a good vigorous ferment under way.

A most satisfying process all round. However, there is one note of disappointment. Given your message below I was expecting / hoping for an OG of 1.055 or above. So I was some what perplexed to get an OG of 1.044! Should this brew ferment out to the hoped for 1.014 this would give me an ABV of some 4%. I am completed bemused by the OG reading; I’ve looked at the process I’ve followed and nothing stands out to me as wrong. Can you see anything in the above that would worry you?

I’d very much appreciate your comment on this; you may recall from our brief chat on Saturday that I’ve had a few kits that have had a disappointing OG, e.g., a Muntons Midas Touch Golden Ale that gave an OG of 1.046 (FG 1.014, ABV 4.2%) and a Woodfordes Norfolk Nog with an OG of 1.041 (FG 1.014, ABV 3.5%). Anything you can add would be much appreciated. Look forward to hearing from you later.

Richard

I want to stress here that I have no problem with Hamstead Homebrew or Chris. They've responded quickly to my queries with ideas as to what the problem may be, and have confessed bafflement at why this has happened. I've posted this to see if anyone else may be able to spot something I'm doing to cause the low OG, especially as this isn't the first kit I've had this happen to. ANY suggestions will be most gratefully received.

Thankyou.

[vacant]

My guess? I suspect your mixing isn't thorough enough. When I do 3 or 3.6Kg kits I warm the tins and pour into the bin, add the 6 pints or so of boiling water using a bit to rinse the tins. THEN, I use my long handled spoon to stir and scrape the base of the bin. Tipping the bin, to expose the base I find there's ALWAYS extract unmixed sticking to the bottom so I scrape that off and stir it in, rotate the bin slightly to expose the next bit of base and continue. So I make sure the entire base has been scraped by the tip of my long-handled spoon. You're unlikely to achieve this with a less thorough stir and then aerating.

If you have just 300g of stuck to the bottom, it will reduce your OG by 10% e.g. 1050 to 1045.

On the plus side it is no big deal, it will probably dissolve over the next few hours by itself and over the next few days the extract will get eaten anyway so no difference to the brew, it's just that OG reading that is a bit out.

[RichardG]

Thanks vacant, that's very interesting. Assuming you're right I could end up having a couple of pints of my 'weak' beer, and end up falling over . Well, let's see. Next time I make up a brew I'll be sure to act as you suggest. The more I think of it, the more it makes sense. In previous brews I've been happy to use tap water, and pretty much let the fall of the water aerate. With this I used bottled water, but was careful pouring it in so as not to make to much mess in the kitchen; must keep SWMBO happy! I was sure I'd given it a thorough stir to aerate, but I suspect that was more up in the liquid than down in the goo.

[Dill]

I’d very much appreciate your comment on this; you may recall from our brief chat on Saturday that I’ve had a few kits that have had a disappointing OG, e.g., a Muntons Midas Touch Golden Ale that gave an OG of 1.046 (FG 1.014, ABV 4.2%) and a Woodfordes Norfolk Nog with an OG of 1.041 (FG 1.014, ABV 3.5%). Anything you can add would be much appreciated. Look forward to hearing from you later.

Richard, are you sure that your calculations are correct?
You State.
Midas Touch Golden Ale that gave an OG of 1.046 (FG 1.014, ABV 4.2%) I make the abv to 4.8% which is .6% more than you calculated and Woodfordes Norfolk Nog with an OG of 1.041 (FG 1.014, ABV 3.5%) and according to my calculations I make this out to be 4.1% abv which again is .6%.
I think that you are losing 0.6% in your calculations somewhere, it doesn’t sound much I know but it does take that little bit extra to your expected outcome e.g. Expected ABV of Norfolk Nog 4.5% is now 4.1% which in my opinion sounds a lot closer than your 3.5%

[Darrinfella]

This has GOT to be the best forum around for finding little bits of info!! Never thought too much about stirring up the bottom sludge for my OG readings. No wonder I keep thinking either I've become a lightweight in the drinking department or homebrew alcohol works on my head differently. My % calculations are probably a bit shy of the real figure.
Thanks, Guys!!

[RichardG]

Thanks to one and all for your responses.

Dill; as to my calculations there's a website I use here; http://www.brewcalcs.com/ which gives 4.3% ABV for the Midas Touch and 3.6% for the Norfolk Nog. I also use the HMRC site here (see Sec.30);

http://customs.hmrc.gov.uk/channelsPort ... 379_146310

This basically states the OG - FG x F = ABV. F is a notional factor used depending on the difference between the OG and FG. For the Midas Touch this gives an ABV of 1046 - 1014 (32) x 0.129 = 4.128%, and for the Norfolk Nog 1041 - 1014 (27) x 0.129 = 3.483%. If you've got something different Dill, I'd be interested in knowing what that is.

Chris-x1; your comments are interesting as they suggest that the OG is what you would expect from such kits. Seeing as Muntons (who, of course, also produce the Woodfordes kits) state that the target FG is 1014, which I achieved with each brew, this means that the ABV I got in each case is the ABV I should expect. If that's so why, I wonder, are Muntons claiming 5% for Midas Touch, and 4.5% for the Norfolk Nog? (retorical question I realise, but if someone can suggest a reason, I'd love to know it!)

[Dill]

Hi again Richard,

The formula that I used is OG-FG/7.46 + 0.5 which came with the instructions from Coopers kits.

So using that formulae your Midas would work out to be 1046(OG)-1014(FG) =32 divided by 7.46 = 4.28 + 0.5 = 4.789 this rounded up will = 4.8

I also have used have online calculators and reached the same outcome, but it seems there are quit a few ways to calculate it, and I am confused now to which is the correct way. After doing a bit more research I think that your way is probably more accurate and I believe that some kits are not living up too their expectations about the ABV of their kits, and Chris is doing an excellent job in pursuing Muntons about what is going wrong with their kits..Nice one Chris.

Now that I’ve come to think about it, the Wherry I brewed, only had a FG of 1016 and even after rousing it I could not get it to go any lower so I just bottled it at 1016 it may not have had the claimed 4.5% ABV but it tasted great all the same (don’t ask me what the OG was as I forgot to take a reading as this was the first kit that I had made for a very long absence)
Lately I have been brewing kits from the Coopers range (replacing sugar with dme) and find that they not only taste real good but ferment out very well too.

[smoggy]

Chris, are you saying that that all 2 can kits made up to 23l will basically have the same OG?

[sparky Paul]

Chris, are you saying that that all 2 can kits made up to 23l will basically have the same OG?

If the kits are 3Kg, i.e. two 1.5Kg cans, the OG should be about the same.

[RichardG]

It may also be worth noting that I don't use the standard Muntons yeast, I use Safale S-04.