Lower gravity than expected - what went wrong?

[Pfadfinder]

Hello guys,

I'm relatively new to home brewing (made 5 beers so far). The method I've been following is crystal malt pre boil, then add dry malt extract and hops and boil for 60 - 90 minutes. My beers usually ended up with 1.045ish OG, but this time the OG was 1.020.

So what went wrong? Did I not use enough DME? Or did I add too much water after the boil? Or a combination of the two?

I couldn't find this topic anywhere, but if it came up before a link would be great. Looking forward to your suggestions.

Thank you!

 

[SimonBackus]

Add more malt! More sugers(maltose)=higher o.g.

 

[mtnagel]

1.020 is extremely low. Like 1-2% ABV low. Can you give us the amounts of DME and water you used?

 

[billl]

By far, the most likely explanation is a measurement error. DME has a fixed amount of sugar in it. If you put it in a fixed amount of water, you get a known SG. So..... if you used the correct amount of DME and topped up to 5 gallons, your OG will be 100% on target. The usual sticking point with the OG measurement is that the topoff water doesn't mix perfectly with the wort. That isn't a problem for your beer, since it all will be uniform after sitting for a couple weeks, but it certainly can mess up your measurements if you pull from a watery sample area.

 

[duboman]

When you say you may have added too much water, can I assume this was a partial boil with top off water and you topped off to the 5-5.5 gallon mark?

If your volumes were correct then you got a bad mix of wort and top off water resulting in a lower, inaccurate hydrometer reading. Common problem

 

[freisste]

So what went wrong? Did I not use enough DME? Or did I add too much water after the boil? Or a combination of the two?

Need your recipe to answer any of these questions.

But as the previous poster mentioned, it is pretty likely that you just didn't get a good mix.

 

[Pfadfinder]

Thanks for your replies everyone.

I followed a recipe for fullers London pride from the book British real ale by graham wheeler. I used:
300g crystal malt which I took out at around 70 deg C.
2000g medium dry malt extract
And target, challenger, north down and Golding hops added at different stages. And Irish moss added at the end for 10 min.
I boiled all of that in ~12L of water and then topped up to ~19L after the boil before pitching the yeast.

Usually for this quantity I would have added another 500g of DME about half way into the boil, but the recipe didn't say about that. That's probably why there is a difference in gravity. Does that make sense?

By the way, could I just use 2500g of DME from the start, or is there a difference to when I start with 2000g and then add 500g later?

 

[Pfadfinder]

@ duboman

'If your volumes were correct then you got a bad mix of wort and top off water resulting in a lower, inaccurate hydrometer reading. Common problem'

Is there a certain ratio I should use? What is a good mix of wort and top off water?

 

[GrogNerd]

by "bad mix" he means "it wasn't mixed enough"

it's called "stratification" the heavier wort/water at the bottom, lighter water/wort at the top and your measurement was taken from the top.

with extract batches, as long as you got your volume right, you can almost guarantee your OG will be what the recipe says it is.

and don't worry, the yeast will find all that sugar and make beer for you

isn't that nice of them?

 

[billl]

2kg = 4.4 lb. DME is about 45 points per lb, so you have about 198 points of sugar. The steeping grains will be 15ish, so a total of 213 sugar points. 19L is about 5 gallons, so that gives 213/5=43 points or 1.043 OG. That was your OG and you had a measurement error. Adding another half kg of DME would add 50 more sugar points, so (213+50)/5=53 or 1.053. Those all could be slightly higher or lower depending on the exact DME and any errors measuring out weights or volumes, but it will be in that ballpark.

In terms of when to add DME, the longer it boils, the darker it gets and it can sometimes pick up a bit of a "twang" off taste. Many people find that if they split the additions with some at 60 minutes and the rest near the end, they can avoid both of those. It's definitely helpful if you are trying to make a very light colored brew.

 

[duboman]

2kg = 4.4 lb. DME is about 45 points per lb, so you have about 198 points of sugar. The steeping grains will be 15ish, so a total of 213 sugar points. 19L is about 5 gallons, so that gives 213/5=43 points or 1.043 OG. That was your OG and you had a measurement error. Adding another half kg of DME would add 50 more sugar points, so (213+50)/5=53 or 1.053. Those all could be slightly higher or lower depending on the exact DME and any errors measuring out weights or volumes, but it will be in that ballpark.

In terms of when to add DME, the longer it boils, the darker it gets and it can sometimes pick up a bit of a "twang" off taste. Many people find that if they split the additions with some at 60 minutes and the rest near the end, they can avoid both of those. It's definitely helpful if you are trying to make a very light colored brew.

+1


Sent from the Commune

 

[Pfadfinder]

Thanks billl! So it's DME in lb * 45 / total wort in gallon...

But how do you work out the steeping grains? And what about the crystal malt, doesn't that add sugar?

 

[billl]

"But how do you work out the steeping grains? And what about the crystal malt, doesn't that add sugar?"

Yes, they do add sugar. Max is somewhere in the 35 points/lb range depending on how dark the crystal is. Most people get less than that by steeping vs mashing with other grains. It's not as clear cut as DME where the manufacture has already extracted all the sugar for you. If it's a small part of your grain bill, it doesn't matter that much though. For 1/2lb, 20 points vs 30 points in a 5 gallon batch is only 1.002 vs 1.003.

 

[Pfadfinder]

So to get the OG up I could add some more crystal malt at the beginning. If I was to add regular sugar, is there a way to work out the difference that would make? And at what point should I add sugar, during or after the boil?

 

[billl]

No, you definitely shouldn't just add more crystal. At this point, I think you need to be following known recipes. Just adding other ingredients to boost OG is NOT a good path to make quality beer. Each ingredient brings different flavors and qualities. eg crystal malts bring a sweet flavor. Just adding a bunch of crystal will give you a very, very sweet beer. On the flip side, regular sugar provides no flavor or body, so adding that would make your beer dry and thinner.

This site has a big recipe section and most have reviews and comments from other brewers. You'll be much better off starting with that type of information. If you brew it as written and think "I wish this were a little more _______", there are plenty of people here would could help you adjust accordingly for the next time you brew it.

 

[Pfadfinder]

Thanks billl, that's very useful!