Best method to raise SG if i come in low pre boil?

[arborman]

I'm going to brew up my second all grain batch this weekend. The last all grain I did, my pre boil gravity was much lower then expected, but I just went with it. If I come in low again on this batch, what would be the best way to raise it up? Add a pound or two of DME, or should I just start out by mashing an extra few pounds of grain? I am batch sparging, so I'm not sure if that's why it came in low?

Thank you for any help!

 

[jflongo]

You can start by adding a little more grain if you have the room in your mash tun. You can also add some DME if you want as well, after you are boiling if it's too low.

 

[kryolla]

do you know how much dme to add? What is your preboil volume and gravity. You can also boil longer

 

[arborman]

Thanks guys.... No, I'm not sure how much DME to add. What math would I use to figure that out?

 

[AnOldUR]

My choice would be to increase all my grains proportionally to the recipe. If your pre-boil comes in high your can dilute and still have the beer that you were aiming for (just more of it) by adding more hops. If you add DME you're throwing your recipe out of balance from its original intent.

 

[Wig]

It is easier to add then take away, so I'd go with extract later. Unless you know your system really well and your typical efficieny, I wouldn't mess with the mash at this point.

 

[Wig]

Thanks guys.... No, I'm not sure how much DME to add. What math would I use to figure that out?

You can use this calc
http://ahomebrewlog.com/gravity_adjustment/

It doesn't take temp into consideration, so be advised.

 

[weirdboy]

It depends how much lower you are.
If you are very low, then adding more grain/extract is a reasonable plan of attack. If it's just a few points, and you are REALLY worried about it anyway (I usually don't worry so much) then you have alternative solutions:

1. MAKE SURE that you have extracted all the good wort from your mash. If you are doing a fly sparge, then you probably have already done this, and can move on to #2. If you are batch sparging (or BIAB) then you can probably collect more runnings to help fix the issue. When I do BIAB, after I pull out the bag, I let it continue to drip into an extra bucket while the wort is coming to a boil. When I use a cooler MLT, I do the same thing--I keep the valve open and let it drip into a spare bucket with the MLT tilted at an angle to get the liquid moving towards the valve. Usually this will collect another quart or so of sweet wort, that I then add to the kettle as the boil is just about to start. This by itself usually improves the gravity situation by a couple of points.

2. If I am still a bit low, I just let the boil go a bit longer to reduce volume a bit. I anticipate this at the beginning of the boil, so I can adjust my hops additions as necessary, and then I double-check my current volume and gravity about 30 minutes into the boil with a refractometer, to make sure I am on target with my adjustments.

 

[ajf]

The best way to increase the pre-boil SG is to stir the sparge water really well when adding it to the mash, then (after sparging), stir the wort really well before taking the sample, and to make sure the sample is at the right temperature before taking the reading.

If the gravity is still low after this, then I would add some light DME to make up the difference. 1 lb DME adds about 45 points to a gallon, so if your pre-boil size is 6.5 gallons, and your pre-boil gravity is 1.040 and it should be 1.050, you want to raise the gravity of the 6.5 gallons by 10 points. 1 lb DME will raise the gravity of 1 gallon by 45 points, or raise the gravity of 6.5 gallons by 45 / 6.5 = 7 points. You would therefore need 10/7 lbs DME to raise the gravity to the required value.

-a.