Strange All graon O.G. Readings

[Tomtanner]

Hello gents,

I've put together a low tech Brutus system and have about 60 gallons brewed on it. At first I noticed my gravity readings coming In very close to what my beer ap states they should come in at. Lately it's been a bit varied however. I have using my refractometer and taking an initial reading as I drain from my mash tun pre boil. This past brew session I was shooting for 1.047 but failed miserably and hit 1.044. I then took another sample after my 60 minute boil prior to pitching the yeast and my measurement was spy on at 1.057.

Should I always take my reading after my boil?

 

[duboman]

Assuming there have been no changes to your system, has there been a change in the crush of your grains? Are you milling yourself and have you checked your gap setting-re-adjust or has someone else been milling for you and their set up changed?

Also, have you verified there have been no changes to your water source? Those are the first two places to look for issues.

 

[Tomtanner]

Assuming there have been no changes to your system, has there been a change in the crush of your grains? Are you milling yourself and have you checked your gap setting-re-adjust or has someone else been milling for you and their set up changed?

Also, have you verified there have been no changes to your water source? Those are the first two places to look for issues.

Good question. I believe my water supply is unchanged and I do use a mill at my brew store that could be inadvertently adjusted by someone else....

My method is basically heat my strike water to about 167-8 and mix water and grains at same time. My temp usually drops immediately to about 148 degrees then I direct fire heat it usually to 152 + based on my recipe. I stir every 5 minutes for the first 30 minutes as I recirculate. After 39 minutes I usually stop storing and only recirculate. After 60 minutes I simultaneously drain the wort to my kettle and add more water to rinse my grains until I collect about 6.25 gallons of wort.

That's basically my process..... Should I make adjustments?

 

[latium]

When during sparging are you taking your measurements? Keep in mind that your gravity is going to be very high on your first runnings (or early on during the sparge, since it sounds like you're fly sparging), while later on, the gravity will drop. Pre-boil gravity is generally taken once all the wort has been collected; this will give you an idea ahead of time if you're going to hit your post-boil target so you can add some extract if you need to boost the OG. (Checking the gravity []iduring[/i] the sparge is useful to make sure you're not oversparging.)

If you're already checking the gravity after you've collected all your wort, then disregard that. However, consider that your 6.25 gallons of wort at 1.044 equates to 1.055 at 5 gallons (sugars don't evaporate, but water does, of course), so you're pretty close there.

My apologies if you already knew this or if it's too basic. Just wanted to be sure those bases were covered.

 

[Tomtanner]

When during sparging are you taking your measurements? Keep in mind that your gravity is going to be very high on your first runnings (or early on during the sparge, since it sounds like you're fly sparging), while later on, the gravity will drop. Pre-boil gravity is generally taken once all the wort has been collected; this will give you an idea ahead of time if you're going to hit your post-boil target so you can add some extract if you need to boost the OG. (Checking the gravity []iduring the sparge is useful to make sure you're not oversparging.)

If you're already checking the gravity after you've collected all your wort, then disregard that. However, consider that your 6.25 gallons of wort at 1.044 equates to 1.055 at 5 gallons (sugars don't evaporate, but water does, of course), so you're pretty close there.

My apologies if you already knew this or if it's too basic. Just wanted to be sure those bases were covered.

This is actually VERY helpful! I didn't take into account water evaporating and sugars bit evaporating. Thus far I have only measured from the brew kettle once everything is gathered. So I take it about 6 gallons for prevail then at the very end after my 60 minute boil.

 

[zachattack]

Yes. Depending on your boiloff you'll see a huge difference between preboil SG and postboil SG. It's good to measure preboil because then you can see if you're off before the boil's started, and you can take corrective action (add DME, dilute with water, etc.). After you've used a system a few times, the boiloff rate should be very predictable.

 

[duboman]

Good question. I believe my water supply is unchanged and I do use a mill at my brew store that could be inadvertently adjusted by someone else....

My method is basically heat my strike water to about 167-8 and mix water and grains at same time. My temp usually drops immediately to about 148 degrees then I direct fire heat it usually to 152 + based on my recipe. I stir every 5 minutes for the first 30 minutes as I recirculate. After 39 minutes I usually stop storing and only recirculate. After 60 minutes I simultaneously drain the wort to my kettle and add more water to rinse my grains until I collect about 6.25 gallons of wort.

That's basically my process..... Should I make adjustments?

Definitely evaluate your crush next time as variation can cause changes in efficiency, better yet, since you seem to be experienced in AG get your own mill and that problem is solved!

As for your volumes and boil off, as long as you are consistently hitting both your pre boil and post boil this should make less of a difference.

If your volumes are beginning to fluctuate then your expected gravitates will be off but not by much unless your are going over/ under a lot