After winning the toss, Northants were rushed out for just 81 in 35 overs despite 38 from opener Emilio Gay, before the home side were then dismissed for a modest 170 in 43.2.
The County then returned to the middle, and were reduced to 23 for five in just 12.5 overs at the close, to hand Essex a lead of 66 runs going into day two on Wednesday.
The only shadow of comfort for Northants is that two of the wickets in the second innings were nightwatchmen in Simon Kerrigan and James Sales, who was bowled with what was the final ball of the day.
Ripley admitted afterwards that he and hs team felt the first hour would be 'challenging' for the batsmen - but insist they had no inkling of the carnage that was to unfold.
“The pitch didn’t look like it would be the tale of the day," admitted Ripley, who is taking charge of his final match as first team coach.
"We thought it might spin a bit and we chose to bat on the balance of trying to get through the first hour where we knew it would be challenging, but knowing it would be challenging for Essex on day four with turn.
"But that went out the wall pretty quickly as the ball nibbled like it did.
“I don’t know how to assess it with the umpires and cricket liaison officer, and it will be interesting to hear what they say about it.
"For 25 wickets to fall in a day’s cricket isn’t what I think people pay to see, but I don’t think there was any intent there.
“There was some disappointing dismissals but a lot of the wickets were genuinely nick offs or hit on the shin.
"I thought the ball moved around excessively for 25 wickets, I don’t think you can put that down to the batters.
“I think if Ben Sanderson had put his hand up to play, he has a bad knee, I would have backed him to bowl well on that surface and inked five wickets next to his name."
And although his team's situation looks bleak, Ripley was refusing to give up on Northants setting Essex a testing total to win the match.
“We have to believe there is a way back because it is such a low scoring match, but we are going to need a full day’s cricket," he said.
"We need Luke Procter (who is unbeaten on 14) to grind it down or am Adam Rossington, Tom Taylor or Josh Cobb striking it out the park and then have a golden spell with the ball to set about some panic.”
Essex fast bowler Sam Cook claimed nine wickets in the day, and he disagreed with Ripley that there was 'excessive' movement off the pitch.
“We rocked up loss the toss but we like to bowl first here at Chelmsford especially with the 10:30am start," he said. "It started like a pretty decent wicket which didn’t have a heap of movement.
“Jamie Porter started really well and it was nice to back him up and then the rest of the day was a bit of a whirlwind.
“On a personal level I liked the pitch but I think when the ball does a bit both teams played pretty positively and there were shots from both teams in there they probably won’t be too happy with.
“When you get on a roll on these sorts of days you have to keep your rhythm and keep on putting the ball in a good area – and we managed to do that.
“There is a bit there but I don’t think it is drastic, there is just enough.
Sometimes when it is the odd ball it draws you in as a batsman.
"Sometimes it is the pitch which doesn’t do it every ball that gets you wickets as a bowler – I think that is the case today. Some days all the nicks carry and all the lbws are given.”