Too Much Maple Syrup at Priming = Exploding Bottles?

So, decided to try a bit of an experiment tonight. My girlfriend and I just finished brewing an altbier with maple sap, and thought...hey, what would that taste like with a little maple syrup at bottling?

So, we did the first half (2.5 gallons) with 2.5 ounces of corn sugar in a cup of water. I had a sample and it tasted well-balanced. Light, a little hoppy, but good.

I took a quick hydrometer reading of the sugar water before we added it and got 1.132. So, I mixed up some of our home made maple syrup, which is a little watery, with a little water and got a hydrometer reading of 1.140. Close enough, I thought (and I promise I corrected for temperature).

Bottled another 2.5 gallons with that, and then sampled the remainder. It was WICKED sweet.

So, now that I've had time to think about it, I'm a little worried that we've just made some bottle bombs. I'm thinking of taking them from our usual closet (which is in the low 70s) and moving them to the cellar (which is in the low 60s).

Can anyone assuage my fears here (or at least tell me to get rid of these things before they blow?)

The question is, what is the sugar content of your maple syrup? The sugar content is going to vary widely depending on the type of "maple syrup" you used. Most of the stuff you get at the store is simply high fructose corn syrup with a little maple flavoring. Others may be more or less real maple syrup. So, the fermentable sugars can be very different between brands and styles. Since this is homemade, I think you're on your own in determining that.

So, a little more information on the syrup you used would be helpful. If it's still really sweet tasting you may have used something that isn't as fermentable, thus leaving more residual sweetness that won't ever ferment out. But it could also mean that the sugar just hasn't fermented yet which is making it taste sweet, but could lead to bottle bombs. But without knowing the fermentable sugar content of what you used it's hard to say for sure.

I have nothing to add, since I am no expert in the sugar content of syrups...

but if that works out for you I think that just might be one heck of a tasty beer.

got my fingers crossed for ya.

I'm not entirely sure how to tell what the fermentable sugar content is...I thought that having a similar hydrometer reading would mean that the corn sugar I put in the first half would have had the same sugar content as the maple syrup i put in the second.

Is there anything else I can try with the remaining syrup to figure that out?

You didn't make bottle bombs. Think of it this way:

The priming solution with corn sugar gets all of its gravity above 1.000 from corn sugar, which is almost entirely fermentable. You can assume that your syrup has some unfermentables in it- they're the parts that make it taste like maple syrup, and not corn sugar. Maple syrup, according to a quick google search, is about 65% fermentable (give or take of course, based on the concentration of your syrup). Basically, the syrup will not be as fermentable as the corn sugar, and if anything the beers carbed with syrup will be a bit undercarbed, though perhaps still quite good (think English beers).

To test the fermentability, you could make a another batch of syrup water, check the gravity, and pitch some yeast into it. The difference between the OG and FG will give you an idea of how fermentable it is. Like I said, though, brewers use corn sugar because it basically ferments entirely out, so anything else you use will be less fermentable, and won't cause bottle bombs.

I wish we could get cool stuff like that here in the south. Do you actually collect the maple "juice" yourself? I saw how they do it the other day on discovery and there is a lot of boiling before it is considered syrup. I bet that would be pretty good in a ESB.

I know this is not 100% applicable but I think it may give a good starting point.

Tasting sweet is not an indication of ferment-able sugar content.....

With Honey, honey tastes sweeter than sugar so one would use less in cooking BUT in brewing, honey is slightly less ferment-able than sugar on about a 74-80% range.

The real question is how much of your maple syrup's sugar is ferment-able? I think we could all "reckon-a-guess" but since it is home made, it may be hard to tell.

I am VERY interested in this as I try to use honey instead of 1 pound of grain in most batches and I also sub in honey for priming sugar. The ratio of honey is 1/2 a lbs or 1/2 cup (same thing) for bottling a 5 gallon batch and for grain sub I had been doing a 1 to 1 ratio. (1 lbs of honey for 1 lbs of grain but I think I would up the honey just a bit to force it a touch closer to 100%, in my next batch. (I have never subbed out more than 1 lbs of grain for honey btw.)

I am also interested in using molasses and maple syrup instead of sugars in specific brews, as these are also widely available in my area.

I hope this helps some, keep us posted and good luck!

hoppymonkey said:

I wish we could get cool stuff like that here in the south. Do you actually collect the maple "juice" yourself? I saw how they do it the other day on discovery and there is a lot of boiling before it is considered syrup. I bet that would be pretty good in a ESB.

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I heard they boil 20 gallons of sap to make 1 gallon of syrup!

If you are in the South, I'm sure you can find a hickory tree. Well, hickory sap can also make a tasty syrup. Just 1) make sure you own the tree or get permission from the owner and 2) try not to kill it. There are tutorials on the web, IIRC.

Enjoy!

Justibone said:

I heard they boil 20 gallons of sap to make 1 gallon of syrup!

If you are in the South, I'm sure you can find a hickory tree. Well, hickory sap can also make a tasty syrup. Just 1) make sure you own the tree or get permission from the owner and 2) try not to kill it. There are tutorials on the web, IIRC.

Enjoy!

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This definitely ranks as the coolest thing I learned today. I definitely know where a hickory tree is and I'm googling techniques as I type.

elkdog said:

You didn't make bottle bombs. Think of it this way:

The priming solution with corn sugar gets all of its gravity above 1.000 from corn sugar, which is almost entirely fermentable. You can assume that your syrup has some unfermentables in it- they're the parts that make it taste like maple syrup, and not corn sugar. Maple syrup, according to a quick google search, is about 65% fermentable (give or take of course, based on the concentration of your syrup). Basically, the syrup will not be as fermentable as the corn sugar, and if anything the beers carbed with syrup will be a bit undercarbed, though perhaps still quite good (think English beers).

To test the fermentability, you could make a another batch of syrup water, check the gravity, and pitch some yeast into it. The difference between the OG and FG will give you an idea of how fermentable it is. Like I said, though, brewers use corn sugar because it basically ferments entirely out, so anything else you use will be less fermentable, and won't cause bottle bombs.

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This seems to be the most logical conclusion to me. Being that corn sugar is basically 100% fermentable and maple syrup would be something less than 100%.

If you are concerned about it and you have a spare picnic cooler or 2, just put your bottles in the picnic cooler and tape the lid shut. If the the lid blows off a bottle, at least the mess will be contained. Just open the cooler once day and check them for the first week or so. After that, most of the fermentation should be done.

JJL said:

This seems to be the most logical conclusion to me. Being that corn sugar is basically 100% fermentable and maple syrup would be something less than 100%.

If you are concerned about it and you have a spare picnic cooler or 2, just put your bottles in the picnic cooler and tape the lid shut. If the the lid blows off a bottle, at least the mess will be contained. Just open the cooler once day and check them for the first week or so. After that, most of the fermentation should be done.

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+1. Put them in something waterproof and hope for the best.

Also, you might want to open the first one outside, just in case. Not that I think these will be bombs or gushers, but just for future reference.

elkdog said:

Maple syrup, according to a quick google search, is about 65% fermentable (give or take of course, based on the concentration of your syrup). Basically, the syrup will not be as fermentable as the corn sugar, and if anything the beers carbed with syrup will be a bit undercarbed, though perhaps still quite good (think English beers).

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I agree with this logic that you won't have bottle bombs (although I have no idea how much of a difference .008 gravity points would make, but I would guess not much since as a percentage it's only about a 5% difference in sugar amount). If you used a hydrometer reading, then, as elkdog said, 100% of corn sugar gravity points are coming from fermentable sugar. Obviously the maple syrup can't have more than 100% of it's gravity points coming from fermentable sugar. Of course, this also assumes the same volume of sugar water as syrup water, which I assume you did.

However, I think there is a small problem with the logic used to guess it would be undercarbonated. That would make sense if you did it by weight or volume, but since you used your hydrometer, that changes things. I don't know this for sure about maple syrup, but I would assume it is similar to honey, and honey is ~80% fermentable. However, the other 20% is almost entirely water, so the sugars in honey are roughly 100% fermentable. That is why if you make a dry mead you can get a gravity below 1.000 (mine is ~.990). I just looked up maple syrup and found out that maple syrup is 33% water, 60% sucrose(fermentable), and the rest is glucose and other sugars. So it seems that the sugars in maple syrup are at least 90% fermentable, and probably roughly 100%.

slowbie said:

However, I think there is a small problem with the logic used to guess it would be undercarbonated. That would make sense if you did it by weight or volume, but since you used your hydrometer, that changes things. I don't know this for sure about maple syrup, but I would assume it is similar to honey, and honey is ~80% fermentable. However, the other 20% is almost entirely water, so the sugars in honey are roughly 100% fermentable. That is why if you make a dry mead you can get a gravity below 1.000 (mine is ~.990). I just looked up maple syrup and found out that maple syrup is 33% water, 60% sucrose(fermentable), and the rest is glucose and other sugars. So it seems that the sugars in maple syrup are at least 90% fermentable, and probably roughly 100%.

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Good point, and nice job finding that info on syrup that I didn't find.

Justibone said:

I heard they boil 20 gallons of sap to make 1 gallon of syrup!

If you are in the South, I'm sure you can find a hickory tree. Well, hickory sap can also make a tasty syrup. Just 1) make sure you own the tree or get permission from the owner and 2) try not to kill it. There are tutorials on the web, IIRC.

Enjoy!

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Couple weeks ago SWMBO and I went out to one of her co-worker's place. They live out in the country, have a bunch of Maple in their back acreage and make their own maple syrup. We were there to help collect sap, drink beer and watch the boil. Chatting with the co-worker's husband he said it was a 40:1 ratio, 40 gallons of sap will get you 1 gallon of syrup (plus or minus depending on a host of factors).

fatmoose said:

Couple weeks ago SWMBO and I went out to one of her co-worker's place. They live out in the country, have a bunch of Maple in their back acreage and make their own maple syrup. We were there to help collect sap, drink beer and watch the boil. Chatting with the co-worker's husband he said it was a 40:1 ratio, 40 gallons of sap will get you 1 gallon of syrup (plus or minus depending on a host of factors).

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Wow! I suppose they could do less boiling if they cheated by adding sugar, but then it wouldn't be 100% maple syrup.

I'd go for the 40:1, personally.