Low OG two brews in a row

[alsch890]

Hi there,

A couple of weeks ago I brewed an American IPA (pale, carahell, carapils) and was aiming for about 65% efficiency (my norm) and an OG of 1.058. Instead it came out around 1.048-1.050. Strange I thought. I'm not saying I am an expert brewer but low OG is not normally an issue. I've had it maybe once or twice ever. I make many mistakes and facepalm moments, but generally not in the gravity arena. I decided to switch up my plans and brew something else today a bit different and see what happened. I did an american wheat (Wheat, pilsner, carapils). Again was aiming for around 1.058 and it has come out around 1.046! Now I am really confused, and slightly concerned.

I can't see what has caused it. My sparge didn't seem too much or too quick or anything. I get the malt crushed at the supplier and they are a brewery and supply many other breweries so I'd hesitate to blame their process. One thing I did wonder is that my boiler has two elements. On these two brews I have switched off the lower power one after the hot break. But I am sure I usually do that anyway. I also scopped off some of the hot break foam to avoid boilovers. I am not sure I normally do that. Could that cause an impact?

I think my mash temps are pretty consistant. I'm not great so I tend to just shoot for 66-67 and this has been the same in both brews.

Any ideas or feedback on potential things to check would be gratefully received.

Cheers!

 

[Dads_Ale]

Hi
Could you let us know the grain bill and final volume, may help to see where the issue is.

 

[Gerryjo]

Do you take a pre boil gravity reading as this will give an indication if you're on target. Your boiler is boiling and I assume your meeting your fermenter target per litres.
Do you stir your mash at all after doughing in as you could be retaining vital sugars in your grain.

 

[alsch890]

Hi
Could you let us know the grain bill and final volume, may help to see where the issue is.

Sure, todays was:
2.8kg wheat
1kg pilsner
500g carapils

19L boil volume, 15l batch. (might be a little over 15). I was shooting for 65% efficiency which is my normal ballpark. and my boiler normally burns off 4l of a 19l boil.

 

[alsch890]

Do you take a pre boil gravity reading as this will give an indication if you're on target. Your boiler is boiling and I assume your meeting your fermenter target per litres.
Do you stir your mash at all after doughing in as you could be retaining vital sugars in your grain.

I stir whilst doughing in, to avoid any clumps. I never know if I stir enough or to much, or too much or too vigoruously....

 

[Gerryjo]

I stir whilst doughing in, to avoid any clumps. I never know if I stir enough or to much, or too much or too vigoruously....

If your mashing for an hour it's worth stirring a few times as this will also help even out the temperature as there is always pockets of low and higher temps.

 

[alsch890]

I just realised I took a photo mid-sparge. I have had another theory. I looked back at a wheat beer I did a couple of years ago which came up really short too, I totally forgot about it. But its the only other time I have brewed with over 50% wheat. So now I am wondering, wheat being considered "sticky" maybe my bazooka filter is too fine? or would that be total b*ll*cks? I did a rye earlier this year that was right on the button though and thats supposed to be sticky too (Although only about 15% rye I tihnk)

I stopped taking a pre-boil OG ages ago. I kept hitting the numbers I expected so didn't see the point. I will make a point of doing so next brew and see where we get to....

 

[cushyno]

Could be a few things causing your low OG.

• Wheat crush. I have had problems with low OG on wheat recipes recently until I began re-crushing the batch of pre-crushed wheat that was causing the problem.
• Only using one element may not be giving you as vigorous a boil, so your boil off may be lower so leading to a thinner wort. That may account for a couple of points, but not as much as 10 points.
• Is the wheat malt definitely malted? If it isn't, that's a lot of work for the pilsner malt to do if it is the only grain with enough enzymes to convert all the starch into sugar.

 

[Dads_Ale]

As per previous replies I would look at the following as potential culprits:

Malt crush - sometimes breweries do crush coarse to suit their equipment and requirements. (its always possible they had their mill set for a course crush). I crush my own but have noticed carahell was a real pain to crush as it was very hard.

Sparging - I use a bazooka filter and have never had any problems with it, even with a lot of wheat or a fine crush. Not sure how you do your sparge but you need to careful and avoid a fast sparge that could cause the sparge water to create a path direct to the outlet, maybe more of a problem with a sticky sparge. My sparge and run off is very slow and it can take me over an hour to get a full boiler (25l).

 

[alsch890]

If your mashing for an hour it's worth stirring a few times as this will also help even out the temperature as there is always pockets of low and higher temps.

Do you mean during the mash take the lid off and give it a stir? I've never done that.

 

[Gerryjo]

Do you mean during the mash take the lid off and give it a stir? I've never done that.

Exactly that just take the lid off and give it a stir 2 or 3 times.

 

[cushyno]

Exactly that just take the lid off and give it a stir 2 or 3 times.

+1 This single action can add a couple of points to your gravity

 

[alsch890]

Exactly that just take the lid off and give it a stir 2 or 3 times.

like at 15, 30, 45 mins give it a stir?sorry for being slow here but I literally never thought of it!

 

[Gerryjo]

like at 15, 30, 45 mins give it a stir?sorry for being slow here but I literally never thought of it!

That's exactly that and a quick thorough stir with lid back on a few times...